Latest ESO telbib papers

The Stellar Origin of ''V-shaped'' Spectral Energy Distributions in Lyα-emitting Little Red Dots Revealed by JWST/MIRI

First Author: Ren, Jian
Instruments: MUSE, VIMOS
ProgramIDs: 185.A-0791, 098.A-0017, 097.A-0160, 096.A-0090, 095.A-0240, 094.A-0205, 1101.A-0127, 096.A-0045, 095.A-0010, 094.A-0289
BibCode: 2026ApJ..1003..150R

Understanding the nature of the high-redshift "V-shaped" little red dots (LRDs) recently uncovered by the James Webb Space Telescope (JWST) is crucial for constraining the early coevolution of galaxies and supermassive black holes (SMBHs). Leveraging deep JWST multiband imaging in the GOODS-S field, we photometrically identify six LRDs from a parent sample of MUSE-selected Lyα emitters (LAEs). Their Lyα line profiles are asymmetric, with suppressed blue wings and narrow widths (FWHM < 300 km s⁻¹). Spectral energy distribution (SED) modeling suggests that, in the absence of MIRI photometry (λ_rest > 1 μm), an active galactic nucleus (AGN) could contribute ∼40% of the rest-frame optical luminosity. However, when MIRI data are included, the long-wavelength emission is well reproduced by stellar populations with strong nebular emission in four sources, independent of the inclusion of an AGN component. Morphological analysis reveals that these systems are compact in the rest-frame optical, while exhibiting more extended structures in the rest-frame UV. These results suggest that AGN activity is not required to explain the observed properties of most narrow-line LRDs in our sample. Instead, they are consistent with being compact, star-forming galaxies, although contributions from low-luminosity or obscured AGN cannot be entirely ruled out. Thus, rest-frame near-infrared observations are essential to interpret LRDs, and infrared excesses alone do not reliably indicate AGN activity.

Revealing the stellar population of the ultra-obscured Galactic globular cluster Glimpse-C02

First Author: Loriga, M.
Instruments: VIRCAM
ProgramIDs: 198.B-2004
BibCode: 2026A&A...709A.186L

In this paper, we present the results of a detailed photometric analysis of Glimpse-C02, one of the most extincted globular clusters of the Milky Way. We built a deep color magnitude diagram spanning ≍10 magnitudes and enabling the very first identification of the main sequence turnoff of the cluster. Due to the extreme reddening conditions of the region where the stellar system is located, a differential reddening correction was necessary. The resulting reddening map shows color excess variations up to δE(B − V) ≍ 2.5 mag in the direction of the target. From isochrone-fitting of the differential reddening corrected color-magnitude diagram, we obtained a new estimate of the mean color excess, E(B−V) = 6.33_−0.04^+0.05, and a distance modulus (m−M)₀ = 14.00_−0.11^+0.26, corresponding to a distance of d = 6.3_−0.3^+0.8 kpc from the Sun, and a Galactocentric distance of 2.6_−0.7^+0.6 kpc. This distance value, within the associated uncertainties, suggests that the cluster may be located closer to the Galactic Center compared to previous estimates, possibly supporting its classification as a bulge globular cluster. Furthermore, we obtained a photometric metallicity estimate of [Fe/H] = −0.30_−0.08^+0.10 and the first absolute age determination for Glimpse-C02, resulting in t = 11.9_−0.6^+0.7 Gyr, as typically measured for Galactic globular clusters at this metallicity. We also obtained a new estimate of the center of gravity of the cluster and determined its projected density profile from resolved star counts, finding a high King concentration parameter (c = 1.97_−0.67^+0.51) and a core radius r_c = 8.72_−0.35^+0.40 arcsec. Finally, from the surface brightness profile of the system, we derived an integrated H-band magnitude M_H = −7.9, corresponding to a mass of M = 3.57_−0.19^+0.22 × 10⁴ M_⊙. Thus, our work classifies Glimpse-C02 as an old and metal-rich globular cluster that is in an advanced stage of its dynamical evolution.

Azimuthal molecular variations in the AB Aur planet-forming disk

First Author: Jiang, Haochang
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2021.1.00690.S, 2012.1.00303.S
BibCode: 2026A&A...713A.334J

Late infall episodes, where material from the surrounding environment accretes onto Class II protoplanetary disks, are emerging as a potentially important but poorly quantified driver of disk evolution. Observed as filamentary streamers in molecular lines and scattered light, such late-stage accretion can perturb disk structures through localized shocks, density enhancements, and warps, yet its chemical consequences remain poorly constrained. We present NOEMA 1.2 mm line-survey observations of the AB Aurigae system, a structured young Class II Herbig disk that shows evidence of both ongoing infall and planet formation. We detected strong azimuthal chemical diversity: SO emission is enhanced in the northern disk near the inferred streamer--disk interaction region, while C₂H emission peaks on the opposite southern side. In contrast, CS forms a nearly axisymmetric ring, while HCN and HCO⁺ peak near the dust continuum overdensity at the main millimeter-sized dust ring. Using multi-transition rotational-diagram analyses of SO and CS, we quantified the azimuthal contrast in column density and excitation. The SO-bright sector exhibits higher rotational temperatures and SO column densities, whereas CS remains nearly axisymmetric with substantially lower rotational temperatures, suggesting that the two species probe different disk layers and/or chemical components. For C₂H, potential temperature variations contribute to but cannot fully explain the observed asymmetries. The HCO⁺/H¹³CO⁺ line ratio further indicates that HCO⁺ is optically thick across the molecular ring, while the elevated ratio inside the cavity suggests an enhanced gas-phase ¹²C/¹³C, consistent with isotope-selective photodissociation. Comparison with gas-grain chemical models favors gas-phase C/O ratios near or above unity, with a higher effective C/O in the C₂H-bright sector. We discuss two plausible, nonexclusive origins for the observed chemical asymmetries: (i) infall-induced heating and desorption of O-bearing ices that enhance SO and lower the local gas-phase C/O near the streamer's impact site and (ii) planet-driven substructures and localized heating or enhanced UV irradiation that can promote hydrocarbon-rich chemistry on the opposite side. These results highlight that environmental accretion and planet formation can jointly imprint azimuthal variations in disk chemistry, with potential consequences for the compositions of forming planets.

Preferential alignment of Class 0 and Class I protostellar disks in multiple systems across nine nearby molecular clouds

First Author: Hsieh, Cheng-Han
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2015.1.00041.S, 2019.1.01792.S
BibCode: 2026A&A...713A.340H

Protostellar disk orientations in multiple systems provide critical insights into the primary mechanisms that govern the formation of multiple-star systems, their subsequent dynamical evolution, and their impact on planet-forming disks. We present a disk alignment study of 512 Class 0, Class I, and flat-spectrum protostars across nine nearby molecular clouds within 500 pc utilizing data from the CAMPOS and VANDAM surveys. Our sample includes 74 binaries and 31 high-order multiple systems. We find that multiple systems with projected pair separations up to 6000 au exhibit preferential disk alignment with respect to each other across all evolutionary classes, deviating significantly from the random distribution predicted by turbulent fragmentation models. This suggests that the formation of multiple systems cannot be explained by turbulent fragmentation alone. Disk alignment on scales of a few thousand astronomical units is also difficult to explain by disk fragmentation as the dominant origin. Further, we find that the degree of nearest-neighbor disk alignment in higher-order multiples is comparable to that in binaries. Finally, we identify a significant deficit of flat-spectrum protostellar disks in high-order multiple systems as compared to younger Class 0 and Class I phases. The decline is consistent with rapid dynamical evolution, in which most higher-order systems dissolve by the end of the Class I phase.

Magnetic fields in massive star-forming regions (MagMaR): VIII. Magnetic field overrun by gravity in GGD 27's accretion streamers

First Author: Fernández-López, M.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2017.1.00101.S, 2015.1.00480.S
BibCode: 2026A&A...713A.246F

Context. Accretion streamers connected to protostellar disks and/or envelopes are thought to transport material across several thousand of au. Whether the motions of the gas comprising these streamers are dominated by gravity, large scale external turbulence or the action of magnetic fields is still under scrutiny. Aims. The aim of this work is to understand the role of the magnetic fields in the star-formation processes, in particular the role that magnetic forces have in potentially leading flows of gas and accretion onto the envelopes and disks orbiting protostars. Methods. First, we try to identify large-scale accretion streamers toward the high-mass Young Stellar Object GGD 27--MM1 and fit their trajectories using the so-called Mendoza model, a modification of the classical model of pure gravitational infalling motion of fluid particles in a potential well. Second, we estimate the strength of the magnetic field associated with the streamers. Then, we determine whether the streamers are dominated by magnetic or centrifugal forces. Results. Inspecting the Atacama Large Millimeter/submillimeter Array (ALMA) H₂CO cube we were able to identify four accretion streamers spreading up to ~7000 au and fit their trajectories in the position-position-velocity space. The polarized continuum emission reveals a good alignment of the magnetic field and the trajectory of the streamers. Using the Davis-Chandrasekhar-Fermi (DCF) method, we derive estimates for the magnetic field strength, find that the streamers are sub-Alfvénic, and discuss (after estimating energy terms for turbulence, ordered motions, magnetic forces, and gravity) a possible qualitative scenario in which, the gravitational well of the GGD 27--MM1 protostar dominates streamer gas motions over turbulence and magnetic forces at distances of ~3000 au.

Tracing the Evolutionary Stage of Low-mass Dense Cores by Using the Abundance Ratio of SO to SO₂

First Author: Tang, Meng-Yao
Instruments: ALMA_Band_7
ProgramIDs: 2017.1.00545.S
BibCode: 2025RAA....25i5020T

Sulfur-bearing molecules are frequently detected in star-forming regions. The abundance ratio of SO to SO₂ (hereafter, SO/SO₂ ratio) has been proposed as a potential evolutionary tracer of star formation because tentative correlations have been found between SO/SO₂ ratio and evolutionary stages. Nonetheless, the lack of high-resolution observations and extensive statistical analyses of large samples raises questions regarding its efficacy as an evolutionary tracer. In this study, we analyze 31 protostellar cores with both SO and SO₂ detection to investigate the relationship between the SO/SO₂ ratio and two evolutionary parameters of chemical richness factor and gas temperatures. The correlations between SO/SO₂ ratio and evolutionary parameters have been found, but these correlations are mainly contributed by low-mass cores rather than high-mass cores. Our findings suggest that the SO/SO₂ ratio serves as a reliable evolutionary tracer for low-mass dense cores. In high-mass cores, the relationship between the SO/SO₂ ratio and evolutionary stage remains ambiguous. This likely arises from both vigorous stellar feedback effects and the potential absence of distinct evolutionary stages analogous to those in low-mass cores. Consequently, higher-resolution observations with expanded statistical samples are required to assess the viability of SO/SO₂ ratio as an evolutionary tracer for high-mass cores.

Leveraging MMW-MMW Double Resonance Spectroscopy to Understand the Pure Rotational Spectrum of Glycidaldehyde and 17 of Its Vibrationally Excited States

First Author: Bonah, Luis
Instruments: ALMA_Band_3
ProgramIDs: 2016.1.00074.S
BibCode: 2025ESC.....9..864B

Broadband measurements of glycidaldehyde in the frequency ranges 75-170 and 500-750 GHz were recorded to extend previous analyses of its pure rotational spectrum in the microwave region. The rotational parameters of the ground vibrational states for the main isotopologue and the three singly 13C-substituted isotopologues were considerably improved, and additional higher-order parameters were determined. To identify new vibrationally excited states in the dense and convoluted spectrum, an updated version of the double-modulation double-resonance spectroscopy technique was used. Connecting transitions with a shared energy level into series and expanding these via Loomis-Wood plots proved to be a powerful method, which allowed the identification of 11 new vibrationally excited states in addition to the already known aldehyde torsions, v21 = 1 to v21 = 6. Interactions between several vibrational states were observed, and three interacting systems were treated successfully. Rotational transitions of glycidaldehyde were searched for in the imaging spectral line survey ReMoCA obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) toward the high-mass star-forming region Sgr B2(N). The observed spectra were modeled under the assumption of local thermodynamic equilibrium (LTE). Glycidaldehyde, an oxirane derivative, was not detected toward Sgr B2(N2b). The upper limit on its column density implies that it is at least six times less abundant than oxirane in this source.

Characterizing Candidate Blazar Counterparts of the Ultra-high-energy Event KM3-230213A

First Author: Adriani, O.
Instruments: ALMA_Band_3, ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2011.0.00001.CAL
BibCode: 2026AJ....172..139A

High-energy astrophysical neutrinos serve as crucial messengers for understanding hadronic acceleration processes and identifying the origins of cosmic rays, with blazars among the most promising neutrino sources. The KM3NeT experiment reported the detection of an ultrahigh-energy neutrino with an energy estimate of ∼220 PeV, the most energetic yet observed. The neutrino arrival direction has a 99% confidence region of 3° radius centered at R.A. 94 .° 3, decl. −7 .° 8 (J2000). In this work, 17 candidate blazars located within this region are identified. Comprehensive new observations and archival data analysis for these sources are presented. The study provides a complete multiwavelength coverage across radio, optical, X-ray, and gamma-ray bands, including proprietary data and dedicated follow-up observations. This study highlights flaring behavior in several candidate counterparts. One object exhibits a radio flare coinciding with the neutrino arrival time, with a pre-trial chance probability of 0.26%. Only for this object, the chance probability could be quantified in a robust way. Another candidate displays a rising trend in X-ray flux in a 1 yr window around the neutrino arrival time, while a third undergoes a gamma-ray flare during the same period. Based on the observational findings presented here, while none of these candidates can conclusively be linked to the neutrino, the implications of a possible blazar origin for the KM3NeT event are discussed.

Low-Metallicity Star Formation Survey of Sh2-284 (LZ-STAR): The Core Mass Function

First Author: Cheng, Yu
Instruments: ALMA_Band_6
ProgramIDs: 2024.1.01580.S, 2021.1.01706.S
BibCode: 2026ApJ..1009L..50C

We present an Atacama Large Millimeter/submillimeter Array 1.3 mm dust continuum study of the dense core mass function (CMF) in Sh2-284, a low-metallicity outer Galaxy star-forming complex with Z ~ 1/3--1/2 Z_⊙. The observations cover six far-infrared bright subregions at ~0 .″ 65 (3000 au) resolution. We identify a total of 91 candidate dense cores and define a robust catalog of 68 cores with Gaussian fitting. The high-mass CMF above 2.5 M_⊙ is well described by a Salpeter-like slope, with a fiducial forward-modeled value of α=1.22-0.22+0.24 for dN/dlogM∝M-α . Together with existing constraints on the initial mass function (IMF) of Sh2-284, the Salpeter-like CMF is consistent with a resemblance between the CMF and IMF shapes in the outer Galaxy environments, suggesting that moderately low metallicity alone does not strongly reshape the high-mass CMF/IMF slope.

Corona Australis 151: An extremely young protostar

First Author: Redaelli, E.
Instruments: ALMA_Band_6
ProgramIDs: 2024.1.00605.S
BibCode: 2026A&A...713L..23R

Context. Prestellar cores are the birthplace of stars and planetary systems, but they are short-lived objects since the initial stages of dense core evolution, collapse, and the formation of a protostellar seed are fast. In an effort to build a catalogue of bona-fide prestellar cores in the solar neighbourhood, we used APEX observations to identify dynamically evolved cores among dense cores observed with Herschel. One of them, Corona Australis 151, stood out because of its centrally peaked structure, with densities above 10⁷ cm^-3 in the central 500 - 1000 au, and high deuteration levels (N₂D⁺/N₂H⁺ ~ 0.5), which are suggestive of an evolved prestellar stage. Aims. Corona Australis 151 appears to be an evolved prestellar core, but the presence of broad wings in some of the detected lines and a tentative 70 μm detection with Herschel partially challenges its status of being in a prestellar stage. We therefore assessed its evolutionary stage. Methods. We analysed new ALMA data of the continuum emission and of several line tracers (including typical outflow tracers) at a resolution of ~150 - 200 au, tracing the envelope. Results. We unveil the presence of a compact and young outflow (projected dynamical age: ~500 yr) traced by SiO, CO, and H₂CO emission. The continuum emission traces an envelope structure of size ~1000 au and mass 0.33 M_⊙ (assuming T_dust = 20 K). Conclusions. Corona Australis 151 is an extremely young protostar, possibly one of the youngest known in the solar neighbourhood, and it can thus serve a new laboratory to study the chemical and dynamical evolution at the dawn of star formation.

Dust substructures and line perturbations driven by a forming planet in J16120

First Author: Sierra, Anibal
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2021.1.00128.L, 2022.1.00646.S, 2023.1.01100.S
BibCode: 2026MNRAS.552g1700S

Hints of planet formation have been independently reported within the gap of the disc around 2MASS-J16120668--301027 from millimetre continuum, infrared, and H

$\alpha$

observations. In this work, we present new evidence for ongoing planet formation based on Atacama Large Millimeter/submillimeter Array (ALMA) Band 7 observations, detecting 0.87 mm dust continuum emission together with

$^{12}$

CO (J = 3--2) and

$^{13}$

CO (J = 3--2) line emission. Visibility modelling of the continuum data reveals an inner disc and two dust rings peaking at 23 and 75 au. The continuum morphology is better reproduced by an eccentric disc model (

$e\sim 0.1$

) than by an axisymmetric disc. We further investigate the gas kinematics through modelling of the

$^{12}$

CO channel maps. The residual line-width map shows a localized increase in velocity dispersion at the position of a previously reported circumplanetary disc candidate (deprojected radius

$\sim$

32 au, position angle

$\sim 170^\circ$

) and along its orbit. This signal is spatially coincident with kink-like features and a transition from sub-Keplerian to super-Keplerian velocities. In addition, the velocity residual map exhibits an arc-like structure extending outward from the planet candidate, while the gas kinematics -- despite substantial uncertainties -- is consistent with inflow towards the candidate's orbital radius. The observed increase in velocity dispersion agrees with predictions from planet--disc interaction simulations, which produce enhanced turbulence both at the planet location and along its orbital path. Taken together, the continuum morphology and gas kinematic signatures provide compelling new evidence for ongoing planet formation within the disc gap.

Baryonic Ecosystem IN Galaxies (BEINGMgII): III. Cool gas reservoirs at 0.3 ≤ z ≤ 1.6 in the Dark Energy Survey

First Author: Chaudhary, Reena
Instruments: VIRCAM
ProgramIDs: 179.A-2010, 179.A-2004
BibCode: 2026A&A...709A.238C

We investigate the origin of intervening cool Mg II absorption detected in the spectra of background quasars and the nature of associated galaxies across a broad redshift range of 0.3 ≤ z ≤ 1.6, and a largely unexplored galactrocentric distance of ≲20 kpc. Using nebular [O II] λλ3727, 3729 emission lines identified in DESI fibre spectra centred on quasars, we detect 342 galaxies at a typical detection rate of ∼0.45% at z ≲ 1, which increases with the Mg II equivalent width (W₂₇₉₆). A significant fraction (74%) of these galaxies are associated with strong absorbers with W₂₇₉₆ ≥ 2 Å. These absorbers trace galaxies spanning stellar masses of 8.4 ≤ log(M_★/M_⊙)≤11.6 and star formation rates (SFRs) of −1 ≤ log(SFR [M_⊙ yr⁻¹]) ≤ 2.7, located at projected galactocentric distances of 4−24 kpc. We find that the average Mg II absorber strength increases from 2.1 Å to 2.8 Å between redshifts of z ∼ 0.4 and 1.2, indicating evolution in the cool gas content of galaxy halos. The relatively constant absorber strength with galactocentric distance implies a clumpy structure of cool gas in the circumgalactic medium (CGM). Further, we find a positive correlation between W₂₇₉₆ versus stellar mass (M_★), and the SFR, suggesting that the distribution of metal-enriched cool gas in the CGM is closely tied to the properties of the host galaxies. The redshift evolution of gas-phase metallicity suggests that strong Mg II absorbers trace the general population of star-forming galaxies. The velocity dispersion of the cool gas increases with halo mass, and the wide range of the line-of-sight velocity offset (−389 to 364 km s⁻¹) between the galaxy systemic velocity and absorbers highlights the dynamical nature of CGM. However, the majority of this gas remains gravitationally bound to the dark matter halos, consistent with a picture of gas recycling via galactic fountains.

Open cluster remnants in the Gaia epoch: I. NGC 1901, Ruprecht 3, Ruprecht 31, and ESO 426 SC26

First Author: Latorre-Soto, J.
Instruments: FEROS, FIDEOS
ProgramIDs: 086.D-0963
BibCode: 2026A&A...713A.313L

Context. Most Galactic stars are born in large groups or stellar clusters, whose final stage before complete dissolution into the stellar field is a collection of a handful of stars, most of which are binaries, called open cluster remnants (OCR). Aims. This study aims to determine whether the potential OCR candidates Ruprecht 3, Ruprecht 31, and ESO 426 SC26 are true star clusters by characterising their member stars based on kinematic and parallax data and studying their behaviour relative to the stellar background. Methods. We used independent radial velocity measurements of thirty-eight stars from the FEROS and FIDEOS spectrographs, as well as precise astrometry from Gaia DR3. Results. The radial velocity analysis shows a relatively low number of binary stars among our selected targets. Furthermore, the analysis of parallaxes, proper motions, and radial velocities shows no evidence of a kinematically and spatially consistent stellar group in the analysed fields. Additionally, we find that the original overdensity measurements are driven only by bright stars, as there is no excess of faint stars within the observed regions. We tested our methods using the well-known OCR NGC 1901. Conclusions. We conclude that none of our three candidates are true OCRs but most likely asterisms. NGC 1901 is a 500 ± 100 Myr-old cluster remnant located 418 ± 6 pc from the Sun composed of no more than 20--25 stars within a 10' radius from the centre.

Very Large Telescope observations of interstellar comet 3I/ATLAS: III. High-resolution monitoring of CN and forbidden oxygen emission across the perihelion passage with ESPRESSO

First Author: Luco, Baltasar
Instruments: ESPRESSO
ProgramIDs: 115.29J6
BibCode: 2026A&A...713A.251L

Context. 3I/ATLAS is only the third known interstellar object to traverse the Solar System, and the first object for which both branches of the perihelion passage can be monitored at high spectral resolution. Aims. We characterize in 3I/ATLAS the heliocentric evolution of the CN production rate and the forbidden [O I] emission, describe the broader emission line inventory, and release the analysis tools and reduced data products to the community. Methods. We obtained high-resolution (R ≃ 140 000) spectroscopy of 3I/ATLAS on 23 nights with VLT/ESPRESSO (r_h = 1.67--2.45 au). The CN production rates were derived by fitting the B²Σ⁺ - X²Σ⁺ band using CometSpec, a publicly released Python package for flexible fluorescence modeling. The three forbidden [O I] lines were modeled to derive the green-to-red (G/R) flux ratio and a CO₂/H₂O proxy. The two quantities were fitted with symmetric and piecewise-asymmetric power laws. Results. We detected CN in 18 of 22 useful nights. We fit Q_CN = a (r_h/1au)^b to the production rate versus heliocentric distance relation. The pre-perihelion CN power-law index is b_pre = -4.62^+1.25_-1.22, which is within the range observed for Solar System comets. The CN residuals about the smooth model show substantial scatter that we attribute to a combination of systematics and possible physical drivers that the current cadence cannot disentangle. The G/R ratio decreases from ~0.42 ± 0.14 at r_h ≃ 2.4 au to ~0.114 ± 0.004 near perihelion. The asymmetric piecewise oxygen fit is strongly preferred over the symmetric fit, consistent with thermal inertia models, although a denser post-perihelion sampling is needed to confirm this. The CO₂/H₂O proxy spans ~0.06--1.06 and is comparable to the values reported by Subaru/HDS and SPHEREx and to those measured for 2I/Borisov. We additionally identify Ni I and Fe I and report post-perihelion production rates for C₂ and CH. Conclusions. Our high-resolution monitoring of 3I/ATLAS reveals a CO₂-rich coma that becomes progressively H₂O-dominated near perihelion, with a G/R asymmetry consistent with delayed H₂O sublimation predicted by thermal inertia models. Together with the public release of CometSpec and the reduced data, these results provide an empirical reference and a methodological framework for the next generation of interstellar object monitoring campaigns.

Beryllium enhancement in stars of the accreted Thamnos-2 system

First Author: Molaro, P.
Instruments: UVES
ProgramIDs: 111.24HT, 65.L-0507, 71.B-0529, 072.B-0585
BibCode: 2026A&A...713A.296M

Context. Surveys of Galactic halo stars have revealed numerous streams and substructures tracing stellar populations accreted by the Milky Way. Among these, Gaia-Sausage-Enceladus (GSE) and Sequoia are the most prominent, both associated with dwarf galaxies accreted about 10 Gyr ago. Aims. We aim to measure beryllium abundances in nine stars associated with Thamnos, a substructure possibly linked to Sequoia, motivated by the discovery of a Be-rich star BPM 3066. Methods. We used Gaia photometry and parallaxes to compute ATLAS9 model atmospheres. Synthetic spectra were generated with turbospectrum and used with MyGIsFOS in single-model mode to analyse UVES high resolution spectra. Results. Four new stars exhibit a significant beryllium overabundance. Moreover, the two known Be-rich stars, HD 106038 and HD 132475, are also consistent with Thamnos membership. Thus, all currently known Be-rich stars appear associated with the Thamnos-2 structure. The Be enhancement is accompanied by elevated Si abundances, and we detect a correlation between Be and neutron-capture elements. No comparable Be-rich population is known elsewhere in the Galaxy, pointing to a rare enrichment event. Conclusions. The measured A(Be)/A(Li) excess ratio bears the imprint of spallation reactions, pointing to a highly energetic event in which fast CNO nuclei fragmented upon collision with the surrounding medium. The silicon overabundance is also consistent with a hypernova origin. Such an event may have rapidly enriched the surrounding gas to [Fe/H] ≃ -1.5, explaining the relatively high metallicities of stars formed from this material despite their old ages (≈13 Gyr).

No statistically significant evidence for a correlation between stellar and planetary composition

First Author: Turner, Daisy A.
Instruments: ESPRESSO, HARPS
ProgramIDs: 2104.C-5013, 282.C-5036, 183.C-0972, 198.C-0169, 1102.C-0249, 1102.C-0923, 082.C-0308, 088.C-0323, 1102.C-0744, 105.20P7, 1102.C-0958, 1104.C-0350, 0101.C-0510, 0101.C-0829, 0102.C-0525, 072.C-0488, 106.218R, 106.21M2, 108.2254, 108.22GM, 110.24CD, 106.21ER, 106.21TJ, 108.22KV, 112.25WB
BibCode: 2026MNRAS.552g1756T

The chemical compositions of planets and their host stars are intrinsically linked, having formed from the same protostellar material. Characterizing this relationship provides key constraints on the processes governing planetary formation and evolution. Focusing on host stars with near-solar chemical abundances limits our understanding of how planetary composition varies across a broader chemical parameter space. Expanding the sample to include stars with compositions markedly different from the Sun is therefore essential for building a complete picture of star--planet compositional connections. Here, we focus specifically on iron-poor hosts since they are more likely to be alpha-enhanced and represent some of the most chemically distinct stars relative to the Sun (i.e. thick disc stars). We present a sample of 45 stars hosting 64 planets across the super-Earth and sub-Neptune regimes, for which we homogeneously obtain new stellar parameters including abundances, re-derive planetary mass and radius, and model the bulk interior compositions of their planetary companions. No statistically significant evidence for a correlation between stellar and planetary composition was found in our sample. We suggest that this null result is primarily driven by the large uncertainties inherent to both compositional proxies, which may obscure an underlying relationship. Quantifying these uncertainties is therefore a critical step that previous studies have not fully addressed. Furthermore, even with improved precision, uncovering such a relation may require a higher-dimensional treatment that accounts for additional parameters such as planetary equilibrium temperature.

Tracing Radial Migration in the Outer Disk: A Comprehensive Analysis of the Old Open Cluster Berkeley 36

First Author: Çinar, Deniz Cennet
Instruments: FLAMES, GIRAFFE, UVES
ProgramIDs: 072.D-0019, 072.D-0309, 072.D-0337, 072.D-0406, 072.D-0507, 072.D-0742, 072.D-0777, 073.C-0251, 073.D-0100, 073.D-0211, 073.D-0550, 073.D-0695, 073.D-0760, 074.D-0571, 075.C-0245, 075.C-0256, 075.D-0492, 076.B-0263, 076.D-0220, 077.C-0655, 077.D-0246, 077.D-0484, 078.D-0825, 079.B-0721, 079.D-0178, 079.D-0645, 079.D-0674, 079.D-0825, 080.B-0489, 080.B-0784, 080.C-0718, 081.D-0253, 081.D-0287, 082.D-0726, 083.B-0083, 083.D-0208, 083.D-0671, 083.D-0682, 083.D-0798, 084.D-0470, 084.D-0693, 084.D-0933, 085.D-0205, 086.D-0141, 087.D-0203, 087.D-0230, 087.D-0276, 088.B-0403, 088.B-0492, 088.C-0239, 088.D-0026, 088.D-0045, 089.D-0038, 089.D-0298, 089.D-0579, 090.D-0487, 091.D-0427, 092.D-0171, 092.D-0477, 093.D-0286, 093.D-0818, 094.D-0363, 094.D-0455, 171.D-0237, 187.B-0909, 188.B-3002, 193.B-0936, 193.D-0232, 197.B-1074, 278.D-5027, 292.D-5043, 381.C-0270, 383.D-0412, 383.D-0594, 386.B-0009, 60.A-9143, 60.A-9800, 71.B-0414, 71.D-0065, 71.D-0127, 71.D-0205
BibCode: 2026AJ....172..236C

We present a chemo-kinematical, structural, and photometric analysis of the old open cluster Berkeley 36 using Gaia DR3 astrometry and photometry together with high-resolution spectroscopy from the Gaia-ESO Survey DR5.1. Applying a Gaussian mixture model to Gaia astrometry, we identify 946 high-probability cluster members. We derive a core radius of 2 .' 63 ± 0 .' 21 and a tidal radius of 14 .' 84 ± 0 .' 47, indicating a moderately concentrated and dynamically relaxed system. By fixing the cluster metallicity to the spectroscopic value of [Fe/H] = -0.19 ± 0.02 dex and adopting an independently determined geometric distance of 4377 ± 510 pc, we minimize the classical age--reddening--metallicity degeneracy and derive a robust isochrone age of 6.8 ± 0.5 Gyr. Independent Ba-based chemical clocks yield a mean age of 7.75 ± 1.94 Gyr, supporting the isochrone solution. The cluster exhibits a high main-sequence binary fraction of 48.0% ± 1.7% and hosts 83 blue straggler star candidates with an extended spatial distribution, contrary to classical mass segregation. Orbit integration shows that Berkeley 36 follows a nearly circular orbit in the outer Galactic disk (R_GC = 11.42 ± 0.44 kpc). Accounting for the Galactic warp and disk flare increases the cluster's maximum vertical excursion by 86% and the local disk scale height by 17%, respectively. Comparison with its chemically inferred birth radius (R_b = 6.71 ± 0.66 kpc) indicates an outward radial migration of approximately 5 kpc, predominantly driven by churning. These results establish Berkeley 36 as a benchmark for investigating radial migration, secular evolution, and the dynamical history of old Galactic open clusters.

JWST Nebular Spectroscopy of SN 2023qov: Circumstellar Dust Emission in a Normal Type Ia Supernova

First Author: Macrie, Colin W.
Instruments: XSHOOTER
ProgramIDs: 114.27JL
BibCode: 2026ApJ..1009..241M

We present panchromatic observations of the Type Ia supernova (SN Ia) 2023qov, ranging from ~2 weeks before to ~1 yr after maximum light. JWST near- and mid-infrared spectra at +276 and +363 days show ~400 K dust emission that cools by ~75 K between epochs, the first unambiguous spectroscopic detection of dust emission in a normal SN Ia. We find that the emission is well described by models of carbonaceous dust placed within ~1 lt-yr of the SN, with a dust mass of ~10^-4 M_⊙. We do not see evidence of active dust creation, suggesting an infrared light echo by preexisting circumstellar dust as the likely source of the emission. The JWST nebular line profiles suggest asymmetric, stratified ejecta, similar to other normal SNe Ia, though a slight double-horn structure in the argon lines indicates a toroidal enhancement. SN 2023qov exhibits a slightly red, fast-declining early light curve (∆m₁₅(B) = 1.47 ± 0.05 mag), from which we determine a ⁵⁶Ni mass of M₅₆ = 0.21 ± 0.04 M_⊙, and a distance of d = 36.0 ± 1.8 Mpc to the SN and its host, NGC 7029. The presence of circumstellar dust around a normal SN Ia has implications both for the progenitor system, suggesting a less than pristine environment, and for cosmology, as a possible source of reddening and extinction that can affect distance inferences.

A Sulfur-rich Atmosphere for the Young Jupiter Analog AF Lep b Reveals Significant Solid Accretion

First Author: Xuan, Jerry W.
Instruments: SPHERE
ProgramIDs: 110.25A4
BibCode: 2026AJ....172..233X

AF Lep b is one of the closest analogs to Jupiter in terms of mass (3--4 M_Jup) and semimajor axis (9 au) amenable to spectroscopic characterization. We present JWST/NIRSpec high-contrast spectroscopy of the planet from 2.85 to 5.3 μm at R ~ 3000, which provide detections of CO₂, H₂S, CH₄, ¹²CO (and ¹³CO), and H₂O, as well as complementary JWST/NIRCam imaging that captures the planet's continuum flux from 4.0 to 4.7 μm. Combining the JWST observations with spectra from VLTI/GRAVITY and VLT/SPHERE (1.0-2.5 μm), we carry out atmospheric retrievals that include the effects of clouds and disequilibrium chemistry while allowing the C, O, and S abundances to vary independently. AF Lep b exhibits metal enrichment across C, O, and S with C/H = 2.9 ± 0.5, O/H = 3.7 ± 0.6, and S/H = 4.7 ± 0.7 times solar (and stellar). The planet's slightly subsolar C/O and C/S are consistent with formation near its observed location, and disfavor formation beyond the CO snowline. The sulfur enrichment in AF Lep b implies significant accretion of disk solids during formation, and we estimate the planet contains 56 ± 7 M_⊕ of solids. The C, O, and S enrichment levels of AF Lep b are similar to those of Jupiter and other super-Jupiters like HR 8799 bcde. We also show that the degree of atmospheric metal enrichment of these imaged planets is similar to the bulk metal enrichment of transiting gas giants with masses greater than ~1 M_Jup, suggesting that the process and efficiency of metal accretion for gas giants may not be strongly dependent on orbital distance or planet mass.

Using VLTI/GRAVITY+ to determine the identity of a third planet candidate in the PDS 70 system

First Author: Trevascus, D.
Instruments: GRAVITY
ProgramIDs: 114.27JS
BibCode: 2026A&A...713L..16T

Detections of protoplanets are rare and protoplanetary disk features mischaracterized as planets are common. PDS 70 is one of only two stars known to host multiple confirmed protoplanets, PDS 70 b and c, and repeat detections of a third point-like source in the system suggest the presence of third inner planet. However, previous observations of this third source are insufficient to distinguish whether it is a planet or a concentrated dust clump in Keplerian motion. Our observations with VLTI/GRAVITY+ did not re-detect this point-like source, suggesting that it is, in fact, a dust clump and not a planet. These observations demonstrate how the angular resolving power of VLTI/GRAVITY+ can be used to distinguish between protoplanets and protoplanetary disk features.

Two inner dust clumps in PDS 70: A third protoplanet traced by trojan material or a substructured inner disk?

First Author: Balsalobre-Ruza, O.
Instruments: GRAVITY, SPHERE
ProgramIDs: 115.29EH, 107.22UJ, 60.A-9801, 113.26PM
BibCode: 2026A&A...713A.252B

Context. The wide cavity in the PDS 70 protoplanetary disk harbors two directly imaged confirmed protoplanets. Several studies have proposed the existence of a third inner planet candidate at ~13 au, labeled as PDS 70 d. While its motion is consistent with a Keplerian orbit, its unusually blue spectrum challenges a planetary interpretation. Aims. We investigated the presence and nature of a third inner planet using new SPHERE and GRAVITY observations. Methods. Using the star-hopping strategy, we obtained new coronagraphic SPHERE/IRDIS observations of PDS 70 in dual-polarization imaging mode in the H band, as well as non-coronagraphic observations with SPHERE/IRDIFS covering the YJHK bands. We also searched for a planetary-like signal using GRAVITY+ in astrometric mode with the four-unit-telescope configuration. Results. We consistently detect two inner emission features with SPHERE: one corresponding to the previously proposed planet candidate at ~13 au and another that appears to share the same orbit but leads it by ~120° (clockwise) with a more elongated morphology. Both features exhibit dust-scattered light spectra while displaying different colors, which may indicate differences in dust grain sizes. We show that such a configuration is consistent with co-orbital dust accumulated at the stable Lagrangian regions of a yet undetected planet, distinct from the previously proposed candidate. The analysis of GRAVITY data at the predicted position of this newly proposed planet has resulted in a marginal (3σ) detection located between the two clumps along the same orbit (ρ = 76.2 ± 0.29 mas, and position angle PA = 226.50 ± 0.21°), and consistent with a ~3 M_Jup planet. This planet-like signal aligns with a narrow shadow detected in the outer disk with SPHERE. Additionally, with SPHERE we detect polarized emission very close to the star, which likely arise from the inner disk, with an inclination of 50° and a PA of ~135°. The fact that the two dust clumps appear embedded within this polarized emission motivates an inner disk-related alternative scenario. Conclusions. We conclude that the emission from the previously reported third planet candidate could arise either from a dust clump trailing a yet undetected planet along the same orbit, or from a rotating substructure within the inner disk. Additional observations are required to further test these two proposed scenarios. In particular, confirming the new GRAVITY planet-like signal would support the use of co-orbital substructures as indirect tracers of embedded planets.

Exploring the radial velocity variations of RY Lup with VLT/ESPRESSO: Binary versus spot hypotheses

First Author: Alqubelat, Hala
Instruments: ESPRESSO
ProgramIDs: 106.20Z8, 110.2483, 111.250K
BibCode: 2026A&A...713A.317A

Stellar multiplicity could plausibly lead to the creation of protoplanetary disc substructures, as tidal forces from a close-in spectroscopic stellar companion have the capacity to carve out gaps and shape disc architecture. However, in young, active systems, radial velocity (RV) signatures are often complicated by stellar activity. We investigate RY Lup, a classical T Tauri star hosting a disc with a ~60 au cavity, where studies with Gaia astrometry and VLT/SPHERE imaging have hinted at an unseen companion. Using high-resolution VLT/ESPRESSO spectra and the least-squares deconvolution (LSD) technique, we analysed RV variations over 327 days. We detected significant line profile variations with a periodic signal of ~3.75 days, aligning with prior photometric estimates. The variations are compatible with a close-in binary system at ~0.04 au and a mass ratio of q ~ 0.6. A combined analysis of RV data and ALMA dynamical mass estimates, using ¹³CO and ¹⁸CO, revealed a highly misaligned system. The nearly face-on binary i ~ 13° is misaligned to both the inner and outer discs i ~ 50° and ~70°, respectively. The derived orbital separation is compatible with the inner disc size, given an inner rim at a = 0.12 au measured by VLTI/GRAVITY, which suggests a highly warped disc structure. Nonetheless, the short orbital period conflicts with the derived eccentricity (e ~ 0.23). To explore alternative explanations, we assessed the impact of stellar spots on RV signals. While the LSD deformations can be modelled by different cool spot configurations, a 15% dispersion in retrieved v sin i values -- coupled with the lack of a significant periodic signal -- suggests that spots alone cannot explain the observed variability. As neither hypothesis has been ruled out, we recommend future combined RV and interferometric monitoring to clarify the nature of spectroscopic variability.

Intrinsic alignment demographics for next-generation lensing: revealing galaxy property trends with DESI Y1 direct measurements

First Author: Siegel, J.
Instruments: OMEGACAM, VIRCAM
ProgramIDs: 177.A-3016, 177.A-3017, 177.A-3018, 179.A-2004
BibCode: 2026MNRAS.552g1691S

We present direct measurements of the intrinsic alignments (IA) of over 2 million spectroscopic galaxies using DESI Data Release 1 and imaging from four lensing surveys: DES, HSC, KiDS, and SDSS. In this uniquely data-rich regime, we take initial steps towards a more tailored IA modelling approach by building a library of IA measurements across colour, luminosity, stellar mass, and redshift. We map the dependence between galaxy type -- in terms of rest-frame colour, strength of the

$4000~\mathrm{\mathring{\rm A}}$

break, and specific star formation rate -- and IA amplitude; the bluest galaxies have an alignment consistent with zero, across low (

$0.05\lt z\lt 0.5$

) and high (

$0.8\lt z\lt 1.55$

) redshifts. In order to construct cosmic shear samples that are minimally impacted by IA but maintain maximum sample size and statistical power, we map the dependence of alignment with colour purity. Red, quenched galaxies are strongly aligned and the amplitude of the signal increases with luminosity, which is tightly correlated with stellar mass in our catalogues. For DESI galaxies between

$0\lt z\lt 1.5$

, trends in luminosity and colour alone are sufficient to explain the alignments we measure -- with no need for an explicit redshift dependence. In a companion paper (Jeffrey et al., in preparation), we perform detailed modelling of the IA signals with significant detections, including model comparison. Finally, to direct efforts for future IA measurements, we juxtapose the colour--magnitude--redshift coverage of existing IA measurements against modern and future lensing surveys.

SN 2018bsz: Significant Dust Formation in a Nearby Superluminous Supernova

First Author: Chen, T.-W.
Instruments: EFOSC2, GROND, MUSE, SINFONI, SOFI, XSHOOTER
ProgramIDs: 0103.D-0523, 0103.D-0697, 199.D-0143, 1103.D-0328, 2101.D-5026
BibCode: 2026ApJ..1009..180C

We investigate the thermal emission and the extinction from dust associated with the nearby (z = 0.0267) superluminous supernova (SLSN) 2018bsz. Our dataset combines daily cadence, simultaneous optical and near-infrared (NIR) coverage up to ~100 days with late-time (+ 1.7 yr) mid-infrared (MIR) observations. At 230 days after the light-curve peak, the supernova (SN) is not detected in the optical, but shows a surprisingly strong NIR excess, with r - J > 3 mag and r - K_s > 5 mag. The temporal evolution of the infrared (IR) light curve allows us to assess whether the MIR emission originates from newly formed dust, either in the SN ejecta or in a postshock circumstellar shell, or instead from an IR echo produced by preexisting circumstellar or interstellar dust heated by the SN radiation. Our radiative-transfer modeling shows that the circumstellar and interstellar echo scenarios cannot simultaneously reproduce the observed IR luminosity and its temporal evolution, and we therefore disfavor these interpretations. In contrast, a scenario in which new dust forms in the SN ejecta at epochs ≳200 days provides a self-consistent explanation for the evolution of the SN flux. We can fit the spectral energy distribution well at +230 days with 5 × 10^-4 M_⊙ of carbon dust, increasing over the following several hundred days to 10^-2 M_⊙ by +535 days. SN 2018bsz is the first SLSN showing evidence for dust formation within the SN ejecta, and appears to form 10 times more dust than normal core-collapse supernovae (SNe) at similar epochs. Together with their preference for low-mass, low-metallicity host galaxies, we suggest that superluminous SNe may be a significant contributor to dust formation in the early Universe.

Spectropolarimetry of five changing-look active galactic nuclei

First Author: Marin, F.
Instruments: FORS2
ProgramIDs: 113.268T
BibCode: 2026A&A...709A.230M

Context. A growing number of active galactic nuclei (AGNs) show dramatic changes in their spectral classification. The mechanisms behind the appearance and disappearance of the optical broad emission lines, as well as the brightening or fading of AGNs, are still elusive. Aims. The goal of this study is to investigate this problem from a different angle by using the unique constraints that (spectro)polarimetry can bring. Methods. We acquired polarized spectra of five "changing-look" AGNs (CLAGNs) using the VLT/FORS2 between July and September 2024, using the 300V grism and a 1″ width slit. The sample consists of IRAS 23226-3843, NGC 1346, NGC 2617, NGC 7582, and NGC 7603. Results. Three of the five targets show newly re-emerged broad-line components associated with low-polarized, often wavelength-independent continua, attributed to electron scattering in an equatorial region seen close to pole-on. Their associated broad Hβ lines are systematically blueshifted, while their Hα profiles are predominantly double-peaked around the central emission wavelength, indicative of a kinematically disturbed or disk-dominated region responding to ionizing continuum changes. The remaining two objects do not show clear evidence of any newly emerged polarized broadline emission. Conclusions. Our findings are consistent with accretion-driven changes as the dominant driver of the observed spectral evolution in CLAGNs, with polarimetric properties that are broadly compatible with this interpretation for four out of the five sources.

Early Planet Formation in Embedded Disks (eDisk). XXIV. Systematic Investigation of Disk Structures based on Visibility Analysis

First Author: Narang, Mayank
Instruments: ALMA_Band_6
ProgramIDs: 2019.1.00261.L, 2019.A.00034.S, 2015.1.01512.S
BibCode: 2026AJ....172..230N

The dust continuum emission from young protostellar disks encodes key information about their mass distribution and early evolution, yet uniform high-resolution comparative studies remain limited. We present a systematic uv-plane analysis of parametric intensity models applied to Atacama Large Millimeter/submillimeter Array (ALMA) Band-6 (1.3 mm) observations of 23 disks (19 protostellar systems, with four being in binary) from the eDisk sample, spanning Gaussian profiles to power-law cores with exponential tails (PLCT), including asymmetric extensions. Gaussian models generally fail to reproduce the centrally peaked emission and extended outer structure observed in most disks, whereas the PLCT framework provides a significantly improved description of radial brightness profiles. Incorporating azimuthal asymmetries further reduces residuals in 15 of 17 inclined disks, indicating that departures from axisymmetry are common at early stages. Only two disks, L1489 IRS and Oph IRS63, exhibit clear gap and ring substructures, while most appear smooth at the spatial resolution and sensitivity of our observations. These systems are among the most evolved in the sample, and the absence of flat-spectrum sources limits the evolutionary range probed, suggesting that the detection of prominent gaps and rings is not common in the earliest phases of disk evolution. Using a uniform definition of disk radius based on the 95% enclosed flux, we find a positive correlation with stellar mass, Rdisk∝M⋆1.5±0.1 , with disks in binary systems systematically smaller than those around isolated protostars. While the models capture overall morphology and large-scale asymmetries, distinguishing intrinsic structures from radiative transfer effects in optically thick regions remains challenging.

MIAO-ALMA: Shocks and Protostellar Outflows in 70 μm Dark Clumps with L/M < 1 L_⊙/M_⊙

First Author: Lin, Shuting
Instruments: ALMA_Band_3
ProgramIDs: 2024.1.01696.S, 2018.1.00101.S
BibCode: 2026AJ....172..218L

To investigate the initial conditions of high-mass star-forming regions, we use SiO (2--1) emission to trace early shock-related kinematics toward 16 70 μm dark and massive clumps with luminosity-to-mass ratios (L/M) <1 L_⊙/M_⊙, as part of the Multiwavelength Line-Imaging Survey of the 70 μm dark and bright clouds (MIAO) project. Using Atacama Large Millimeter/submillimeter Array observations at a spatial resolution of ~0.06 pc and a velocity resolution of 0.21 km s^-1, we identify a total of 37 outflows with a variety of morphologies. Outflow parameters were derived by integrating the HCO⁺ (1--0) line wings, excluding the quiescent dense core component traced by H¹³CO⁺ (1--0). We find that outflow masses and velocities show moderate positive correlations with the masses of their driving cores. Owing to the high sensitivity of our observations, which yield longer projected outflow lengths compared to previous studies, the derived outflow dynamical ages span ~10³--10⁵ yr. We detect six narrow-line-width (0.6--1.4 km s^-1) and three broad (>2 km s^-1) SiO (2--1) features not associated with outflows driven by clearly identified protostars. Lacking coincident 3 mm dust continuum cores, their origins may be young outflows from undetected low-mass protostars, dissipating shocks, cloud--cloud collisions, or projection effects when the outflows lie close to the plane of the sky. The detection of these shocks and outflows in such extremely young environments demonstrates that protostellar activity has already begun.

The ALMA EGO-10 survey of massive protoclusters: correlation of 1.3 mm continuum source clustering with evolutionary state

First Author: Logue, Michael C.
Instruments: ALMA_Band_6
ProgramIDs: 2017.1.00983.S, 2016.1.00747.S
BibCode: 2026MNRAS.552g1573L

Massive stars characteristically form in clustered environments. Characterizing young massive `protoclusters' is therefore crucial to constraining the mechanism(s) of massive star formation, and of the assembly of stellar clusters. We present 1.3 mm continuum results from the ALMA (Atacama Large Millimeter/submillimeter Array) EGO-10 imaging survey, targeting 10 Spitzer GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire) Extended Green Objects (EGOs) -- massive protostars with active outflows traced by extended 4.5 μm emission. Our sensitive 1.6 arcmin

$\times$

1.6 arcmin mosaics reveal rich protoclusters associated with all targets. With a mean spatial resolution 2200

$\times$

1600 au, we identify 570 cores -- between 13 and 135 per field. We quantify protocluster structure with the

$\mathcal {Q}$

-parameter, finding structural diversity with 0.5

$\lesssim \mathcal {Q}\lesssim$

0.9. The sample is notable for the wealth of complementary high-resolution multiwavelength data available. Correlating our cores with these observations, we find only 2 per cent, 5 per cent, and 4 per cent of cores host 6.7 GHz CH

$_3$

OH masers, 22 GHz H

$_2$

O masers, and cm--

$\lambda$

continuum sources, respectively. The massive protostars traced by 6.7 GHz masers typically reside near protocluster centres (median offset 0.045 pc), and all at

$d\lt$

3 kpc are found in clustered locales, with >10 cores within 10 000 au. Using VLA (Very Large Array) cm--

$\lambda$

continuum observations, we construct a new evolutionary indicator: the ratio of protocluster cm--

$\lambda$

continuum luminosity to the mass of the associated ATLASGAL (APEX Telescope Large Area Survey of the Galaxy) clump (

$L_\text{cm}/M_\text{AGAL}$

). This ratio correlates positively with

$\mathcal {Q}$

, with the correlation driven primarily by the cm--

$\lambda$

continuum emission from massive young stellar objects (MYSOs). This suggests dynamic protocluster structure, evolving from subclustered to centrally condensed, consistent with the global collapse in hierarchical, clump-fed models of massive star formation.

ACES. VII. Compact Continuum Source Catalog of the Central Molecular Zone

First Author: Wallace, Jennifer
Instruments: ALMA_Band_3
ProgramIDs: 2021.1.00172.L
BibCode: 2026ApJ..1009..130W

The central molecular zone (CMZ) resides in the inner few hundred parsecs of our Galaxy, and despite being the largest reservoir of dense molecular gas in the Milky Way, it has a relatively low present-day star formation rate (SFR) of ~0.08 M_⊙ yr^-1. Continuum and spectral line observations from the Atacama Large Millimeter/submillimeter Array (ALMA) CMZ Exploration Survey (ACES) provide the first full-coverage, high-resolution map of the inner 200 pc of the CMZ at 3 mm. In this paper we present the ACES catalog of compact continuum sources, the most complete catalog of potential sites of star formation in the CMZ to date. Using an automated dendrogram-based source extraction procedure in combination with a by-eye morphological classification scheme, we produce a ``full'' catalog of 1735 detections in total. Additionally, we use spectral index measurements to generate a ``filtered'' catalog of 567 sources with minimal contamination from nonthermal filaments and extended free--free emission. We find that 359 (~63%) of the filtered catalog sources are located at column densities <10²³ cm^-2, outside of the densest molecular cloud regions, 195 of which have not been identified in previous surveys. After cross-referencing with various catalogs generated from data at different wavelengths, we consider it likely that many of these newly discovered detections are produced by pre-/protostellar sources or compact H II regions.

Searching for Embedded Protoplanets with the Keck/NIRC2 Vortex Coronagraph: Confirmation of a Core-accretion Planet in the Narrow Gap of the Elias 2-24 Disk

First Author: Bernardi, Andrea
Instruments: ALMA_Band_6
ProgramIDs: 2013.1.00498.S
BibCode: 2026ApJ..1009L...3B

We present high-contrast imaging observations of seven stars obtained with the Keck/NIRC2 vortex coronagraph between 2018 May and June in the L' and M_s bands. All targets host protoplanetary disks with substructures such as gaps and cavities, potentially tracing ongoing planet formation. Our aim is to assess whether these embedded planets can be directly detected. We reduced the observations with a custom pipeline based on the VIP Python package. Postprocessed images were obtained using angular differential imaging and reference differential imaging combined with principal component analysis. Finally, 5σ contrast curves and detection limits were derived for all targets. We confirm the planetary candidate around Elias 2-24, previously proposed in the literature, at a separation of 394 ± 31 mas (54.9 ± 4.3 au) and a position angle of 298 .° 8 ± 3 .° 2, within the narrow gap of the protoplanetary disk. Comparing the derived photometry with 1 Myr isochrones, we infer a mass between 1.9 and 4.0 M_Jup for Elias 2-24 b, without considering accretion effects, in agreement with estimates considering the properties of the gap and planet--disk interactions. For all the systems in the survey, the 5σ detection limits reach sensitivities down to 1--11 M_Jup at separations ≳0 .″ 25. Since Elias 2-24 b (age ≲1 Myr) is the youngest exoplanet discovered to date, its confirmation has important implications for planet formation timescales and the origin of the gaps observed in very young disks.

Magnetically guided accretion and extremely slow rotation in a metal-enriched white dwarf

First Author: Bagnulo, S.
Instruments: FORS2
ProgramIDs: 115.27UN, 116.2921, 116.2ASX, 0103.D-0029, 0102.D-0045
BibCode: 2026A&A...713A.220B

White dwarfs that show atmospheric metal enrichment offer a direct window into the bulk composition of exoplanetary material and provide some of the most direct constraints on the building blocks of rocky exoplanetary systems. Recent work has suggested that magnetic fields may influence how this material is accreted, potentially channelling debris along field lines and retaining it near magnetic poles rather than allowing it to be redistributed uniformly across the stellar surface. Here we report the discovery of photometric, spectroscopic, and spectropolarimetric variability in the magnetic DZ white dwarf WD 1532+129, revealing a rotation period of about 289 d, by far the longest directly measured for any degenerate star thus far. The observed period may result from the combined effect of angular-momentum loss during the evolution leading to the white-dwarf stage and an unusually slowly rotating progenitor, perhaps a magnetic Ap star. The white dwarf exhibits surface abundance inhomogeneities, with metals concentrated near both magnetic poles, and the observed modulation is consistent with localised metal-rich regions aligned with the magnetic geometry. WD 1532 + 129 is the third of four known magnetic DZ white dwarfs within 20 pc to show evidence of polar metal enhancement, indicating that magnetically guided inhomogeneities are a common property of magnetic metal-enriched white dwarfs.

Giant Planets and Eccentric Orbits are Common around Galactic Thick Disk Stars

First Author: Ferreira, Thiago
Instruments: HARPS, NIRPS
ProgramIDs: 082.D-0499, 083.D-0549, 081.D-0066, 080.D-0408, 086.D-0078, 080.D-0047, 0102.C-0338, 072.C-0488, 198.C-0836, 183.C-0972, 192.C-0852, 196.C-1006, 091.C-0936, 077.C-0364, 085.C-0063, 106.215E, 111.2506, 099.C-0374, 105.20AK, 0100.C-0474, 0101.C-0623, 093.C-0919, 0100.C-0847, 60.A-9700, 094.C-0901, 096.C-0053, 083.C-1001, 092.C-0579, 095.C-0040, 086.C-0230, 094.C-0797, 093.C-0062, 60.A-9709, 096.D-0402, 0103.C-0548, 0101.C-0232, 097.C-0090, 0100.C-0414, 084.C-0229, 086.C-0284, 60.A-9036, 090.C-0849, 082.C-0212, 085.C-0019, 099.C-0458, 190.C-0027, 087.C-0990, 089.C-0050, 088.C-0011, 084.D-0591, 091.D-0469, 0102.C-0584, 0104.C-0090, 0103.C-0206, 196.C-0042, 089.C-0732, 0100.C-0097, 091.C-0034, 097.C-0021, 112.25YG, 108.22KV
BibCode: 2026AJ....172..211F

Planet formation in the Galactic thick disk is expected to be inefficient---low solid reservoirs, short disk lifetimes, and harsh irradiation environments should conspire to inhibit the assembly of planetary bodies---yet, planets are there, and they are stranger than we expected. Here, we present a homogeneous characterization of 32 exoplanetary systems orbiting chemically and kinematically confirmed thick disk stars, combining new detections with a systematic reassessment of archival systems, increasing the total number of exoplanets orbiting thick disk stars to 66. When planets form in the thick disk, a notable fraction are giants and move on more eccentric orbits than their thin disk counterparts---two results that challenge standard disk-evolution models. However, this should be interpreted with caution given detection biases and sample size. We also report TOI-1927 b and TOI-2643 b, the first puffy, low-density giant planets known to orbit thick disk stars, unexpected in old, metal-poor environments where planets should cool and contract efficiently. Together, these findings reveal an early Milky Way far more hospitable to planetary diversity than its harsh conditions would initially suggest. *This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

Upside down: GJ 3090 b the first retrograde exoplanet around an M dwarf detected with NIRPS

First Author: Carteret, Yann
Instruments: HARPS, NIRPS
ProgramIDs: 112.25P3
BibCode: 2026A&A...713L..15C

The angle between stellar spin axis and planetary orbital plane can provide key insights into the formation and dynamical evolution of planetary systems. In particular, this measurement in multi-planet systems can be used to further discriminate between different competing migration scenarios. We present six transit observations of the sub-Neptune GJ 3090 b obtained with NIRPS and HARPS. GJ 3090 b is the inner planet of a confirmed multi-planet system orbiting an M dwarf (M2). Using high spectral resolution and high temporal cadence spectroscopic observations, we analyzed the Rossiter-McLaughlin (RM) effect induced by GJ 3090 b to determine its orbital obliquity. Through the RM revolutions technique, we find that the planet is on a retrograde orbit with a derived 3D obliquity of ψ = 136⁺²⁴_-18 deg ψ = 136 - 18 + 24 deg . We find no evidence of massive outer planetary or wide stellar binary companions, which disfavors scenarios involving gravitational perturbations from a massive body and instead points toward a primordial misalignment of the protoplanetary disk. Our results establish GJ 3090 b as the first planet on a retrograde orbit discovered around an M dwarf and the first highly misaligned confirmed multi-planet system without a known massive companion. We further propose late secondary disk accretion around GJ 3090, in which the disk is not expected to be aligned with the stellar spin axis, followed by disk-driven migration as the most likely mechanisms to explain the observed architecture. This work also illustrates the capability of the RM revolutions technique when applied to near-infrared data to probe orbital architectures of the smallest planets around M dwarfs that have remained mostly inaccessible.

MAGNUS. II. Rotational Support of Massive Early Type Galaxies Decreased Over the Past 7 Gyr

First Author: Mozumdar, Pritom
Instruments: MUSE
ProgramIDs: DataDoiProID
BibCode: 2026ApJ..1009...87M

Understanding how the internal kinematics of massive galaxies evolve is key to constraining the physical processes that drive their assembly. We investigate the evolution of rotational support in massive ( logM*/M⊙>=10.6 ) early-type galaxies (ETGs) over the past ~7 Gyr. We use MUSE integral-field spectroscopic (IFS) data for 212 ETGs at intermediate redshift (0.25 < z < 0.75) from the MAGNUS sample. We compare their kinematics to a carefully matched local sample of 787 ETGs (z <= 0.05) from the MaNGA survey. Using the specific stellar angular momentum proxy, λ_R, we quantify the balance between ordered rotation and random motions. We derive intrinsic λ_R values by applying a uniform correction for seeing and point-spread function (PSF) effects to both samples. We find a significant evolutionary trend: The intermediate-redshift ETGs are systematically more rotationally supported than their local counterparts. The median PSF-corrected λ_R for the MAGNUS sample is 0.48 ± 0.05, substantially higher than the median of 0.34 ± 0.03 for the matched MaNGA sample. This corresponds to a positive slope in the λ_R-z relation of dλ_R/dz = 0.25 ± 0.04 for the combined sample. The decline in rotational support is most pronounced for the most massive ( logM*/M⊙>11.3 ) and highest-velocity-dispersion (σ_e ≳ 200 km s^-1) galaxies. Our results provide robust evidence that massive ETGs have undergone significant kinematic evolution, losing angular momentum as they evolve towards the present day, consistent with theoretical models where processes such as dry mergers play a crucial role in shaping the dynamical state of galaxies.

MAGNUS. I. A MUSE-DEEP Sample of Early-type Galaxies at Intermediate Redshift

First Author: Mozumdar, Pritom
Instruments: MUSE
ProgramIDs: 095.A-0181, 097.A-0909, 095.A-0653, 0102.A-0642, 0104.A-0489, 2101.B-5053, 2101.B-5008, 096.A-0105, 0100.A-0763, 099.A-0292, 097.A-0269, 0102.A-0135, 105.20C9, 106.21AD, 094.A-0525, 0100.A-0249, 0103.A-0157, 095.A-0570, 094.A-0289, 1101.A-0127, 096.A-0045, 095.A-0010, 094.A-0131, 096.A-0222, 0102.A-0327, 096.A-0596, 0103.A-0563, 0100.A-0607, 0101.A-0282, 094.A-0247, 097.A-0254, 095.A-0118, 0102.B-0741, 096.A-0710, 60.A-9195, 094.A-0115, 299.A-5028, 096.A-0496, 0101.A-0506, 294.A-5032, 095.A-0525
BibCode: 2026ApJ..1009..149M

We present a sample of 213 early-type galaxies (ETGs) at redshifts 0.25 < z < 0.75. We combine deep integral-field spectroscopy from the MUSE-DEEP survey with high-resolution Hubble Space Telescope (HST) imaging to study the structure, kinematics, and stellar populations of these galaxies. We measure spatially resolved stellar kinematics and use the specific angular momentum proxy, λ_R, to classify galaxies into fast and slow rotators. The kinematic and photometric axes of fast rotators are generally well aligned, similar to their local counterparts. We find that global stellar population properties, such as age, metallicity, and mass-to-light ratio (M_*/L), correlate strongly with the central velocity dispersion (σ_e), following trends established for local ETGs. Slow rotators are typically more massive, have higher σ_e, and are more metal rich than fast rotators. We also find a slow rotator fraction consistent with local Universe samples. Our findings indicate that the fundamental structural, kinematic, and stellar population scaling relations of massive ETGs were already in place by z ~ 0.75, suggesting their evolutionary pathways have remained stable over the last ~7 Gyr.

A multiband catalog of infrared-excess sources in the Vela-Carina Region: VVVX, DECaPS, and GLIMPSE

First Author: Torres, R. M.
Instruments: VIRCAM
ProgramIDs: 198.B-2004
BibCode: 2027NewA..13002654T

Large multiwavelength surveys of the Galactic midplane enable the identification of sources exhibiting infrared excess, a signature of circumstellar material; however, this task is hindered by high extinction and severe source crowding. We aim to construct a homogeneous catalog of infrared-excess candidates in a ~7.0 deg² field of the Vela--Carina region and to characterize the nature of their excess emission through spectral energy distribution (SED) analysis. We combine optical photometry from the Dark Energy Camera Plane Survey (DECaPS), near-infrared (NIR) photometry from the VISTA Variables in the Vía Láctea eXtended survey (VVVX), and mid-infrared (MIR) photometry from the Spitzer Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) using hierarchical positional cross-matching. Infrared-excess candidates are selected based on photometric quality criteria and MIR color diagnostics. Their SEDs are analyzed with the Virtual Observatory SED Analyzer (VOSA) using grids of theoretical stellar atmosphere models. Photogeometric distance estimates were adopted for the physical characterization of the sources, while variability information from Gaia Data Release 3 (Gaia DR3) and the Near-Earth Object Wide-field Infrared Survey Explorer Reactivation mission (NEOWISE) was used as a complementary diagnostic. From the matched VVVX--GLIMPSE--DECaPS catalog of 249719 sources, we identify 1512 objects exhibiting MIR excess, of which 191 have complete 12-band photometry with S/N>10, enabling detailed SED analysis. For sources with available estimates, the adopted photogeometric distances are statistically consistent with the corresponding geometric distances for nearly the entire sample. The SED analysis independently supports the MIR-excess nature of the majority of the selected sources, indicating infrared emission beyond that expected from stellar photospheres alone. Approximately 15% of the sources are flagged as variable by Gaia, while NEOWISE light curves reveal MIR variability at the level of a few tenths of a magnitude. Comparisons with previously published young stellar object (YSO) and variability-selected catalogs show varying degrees of overlap, with particularly limited overlap with variability-selected samples, indicating that MIR-excess selection provides a complementary route to identifying candidate YSOs in the Vela--Carina region. The resulting catalog provides a well-defined sample of MIR-excess sources with homogeneous multiband photometry, SED characterization, distance information, and variability diagnostics, and constitutes a robust foundation for future spectroscopic and time-domain studies.

The emergence of a [WC] star in Sakurai's object

First Author: Marcolino, W.
Instruments: FORS2
ProgramIDs: 111.24P1
BibCode: 2026MNRAS.552g1533M

Sakurai's object provides a rare opportunity to observe stellar evolution on human time-scales. Since its born-again event and detection in 1996, its evolution has been extensively monitored, and recent optical spectroscopy has suggested the emergence of [WR]-type emission features. In this letter, we present a secure spectroscopic identification of its central star based on new VLT/FORS2 observations and NLTE expanding atmosphere models. Several observed emission lines arise in a [WR]-type stellar wind, establishing the central star as a [WR] object. The strongest stellar features are due to C II--III and He I. We derive the stellar and wind parameters of Sakurai's object and discuss its evolutionary status. The [WR] star is much cooler (

$T_\mathrm{eff} \sim$

30.5 kK) than the born-again star V605 Aql (

$T_\mathrm{eff} \sim$

95 kK), which erupted about 80 yr earlier. The inferred temperature is lower than predicted by models suppressing convective mixing efficiency during the VLTP, but is consistent with higher time-resolution calculations involving slightly lower-mass (

$\lesssim 0.6$

$_\odot$

) remnants. Continued spectroscopic monitoring and atmospheric modelling will be crucial for tracing its reheating curve and constraining the physics of this rapid evolutionary phase.

Common Excitation Patterns of Star Formation, Active Galactic Nuclei, and Shocks in Seyfert Galaxies

First Author: Zhu, Peixin
Instruments: MUSE
ProgramIDs: 60.A-9339, 095.B-0934, 094.B-0321, 099.B-0242, 098.B-0551, 095.B-0532, 097.B-0640, 106.21C7, 110.23PU, 112.25VE
BibCode: 2026ApJ..1009...30Z

The growth of galaxies and their central supermassive black holes is closely connected, yet the net effect of active galactic nucleus (AGN) feedback on host-galaxy star formation remains uncertain. AGN may enhance, suppress, or have little measurable impact on star formation, but distinguishing among these outcomes requires separating star formation and AGN photoionization from shock excitation, which is expected in AGN-driven outflows but has been difficult to isolate. Here we apply a recently developed theoretical three-dimensional diagnostic diagram, designed to separate star formation, AGN, and shock excitation, to Very Large Telescope/MUSE integral field unit observations of nine nearby (z < 0.026) Type 2 Seyfert galaxies. We find a common excitation pattern across the sample: star-forming rings or arcs at projected radii of r ~ 0.8--6 kpc, AGN-photoionized bicones extending to kiloparsec scales, central fast-shock-dominated regions that often extend perpendicular to the AGN bicone, and pure-shock-dominated regions surrounding the central fast shocks and appearing locally within the star-forming rings. Deep Chandra X-ray morphology independently supports this decomposition. The circumnuclear star-forming rings are consistent with bar-driven resonances, although positive AGN feedback may also contribute. The central fast shocks are broadly consistent with AGN jet--interstellar medium (ISM) interactions, while AGN wind--ISM interactions may also play an important role in galaxies with low-power jets. These results establish central shocks as a common feature of Seyfert galaxies and demonstrate the importance of accounting for shock excitation in AGN feedback studies.

White dwarfs within 13 pc: insights from ultraviolet spectroscopy

First Author: O'Brien, Mairi W.
Instruments: UVES, XSHOOTER
ProgramIDs: 099.D-0661, 1103.D-0763, 167.D-0407, 097.D-0063, 097.D-0064, 098.D-0392, 165.H-0588, 109.234T
BibCode: 2026MNRAS.552g1669O

We present a comprehensive multiwavelength spectroscopic and photometric analysis of the 44 confirmed white dwarfs within 13 pc of the Sun. Combining flux-calibrated ultraviolet spectroscopy from the Hubble Space Telescope (Space Telescope Imaging Spectrograph and Cosmic Origins Spectrograph) with ground-based optical spectroscopy, as well as photometry from Gaia, Two Micron All-Sky Survey, and Wide-field Infrared Survey Explorer, we employ a combined fitting method to calculate atmospheric parameters. Each white dwarf is fitted with a bespoke model depending on its detailed atmospheric composition. Two strongly magnetic stars could not be fitted due to the complex splitting of their spectral lines. We find a systematic discrepancy in hydrogen-atmosphere white dwarfs with effective temperatures below 10 000 K, where fits incorporating ultraviolet spectra result in effective temperatures that are 1--5 per cent higher than those derived from optical and infrared photometry alone. We re-classify three helium-atmosphere white dwarfs as metal enriched following a magnesium detection in their near-ultraviolet spectra: WD 0435--088, WD 1132--325, and WD 1917

$+$

386. In total, we identify five stars in the sample for which metals are only detected in the ultraviolet. Overall, we find that 30 per cent of the 13 pc white dwarfs show spectroscopic evidence of evolved planetary systems. Our analysis reveals no measurable difference between the hydrogen content of DQ and DC white dwarfs, although the upper limits of carbon in DCs are significantly below that of the DQ population. We find a multiplicity fraction of 33 per cent for the 13 pc white dwarfs.

The refractory fraction of phosphorus in planet-forming discs

First Author: Borthakur, Sandipan P. D.
Instruments: FEROS
ProgramIDs: 077.D-0092, 082.D-0061
BibCode: 2026A&A...713L..13B

Context. Phosphorus (P) is an essential element for life on Earth and a potential tracer of planet formation history. However, there has been no detection of P-bearing molecules in protoplanetary discs so far. Herbig Ae/Be stars constantly accrete matter from their protoplanetary disc, which alters the composition of the stellar photosphere due to their shallow convective or fully radiative envelope. The altered surface composition reflects the composition of the accreting matter, and thus, that of the inner protoplanetary disc. This accretion contamination of stellar photosphere can persist after accretion has ended in young A- and B-type stars (age ≲ 50 Myr). Aims. We quantify the fraction of P that is locked in dust (the refractory fraction of P) compared to gas in the inner protoplanetary disc around Herbig Ae/Be stars. Methods. We measured the stellar parameters and abundance of five Herbig Ae/Be stars using optical and UV spectra to compare their P and Fe abundances. We also used a ~20 Myr old main-sequence B-type star, whose P and Fe abundance was estimated from an optical spectrum. Fe is assumed to be completely locked in refractory reservoirs in the inner disc. A parametrised relation between the stellar P and Fe abundance gives the fraction of P that is locked in refractory reservoirs. Results. The refractory fraction of P in the inner protoplanetary disc is >=96% within the 95th percentile of the posterior distribution. The reference P abundance for young stars in the solar neighbourhood is -6.66 ± 0.05, which is similar to solar values. Conclusions. Consistent with a previous finding in the HD 100546 system, we conclude that most of the P in the inner protoplanetary disc is locked in dust, likely in refractory minerals such as schreibersite or apatite. Our result, combined with the low cosmic abundance of P, is also consistent with the lack of infrared and millimeter-wavelength observations of P-bearing molecules in protoplanetary discs to date.

Unveiling Metal Mixing in a Grand-design Spiral: A UV/Optical Multiphase Spatially Resolved Study of M83

First Author: Ranjan, Adarsh
Instruments: MUSE
ProgramIDs: 097.B-0640, 097.B-0899, 0101.B-0727, 096.B-0057
BibCode: 2026AJ....172..207R

We present a spatially resolved, multiphase study of chemical enrichment around young star clusters (YSCs) in the nearby grand-design spiral M83 by combining far-ultraviolet (UV) absorption-line spectroscopy from the Hubble Space Telescope Cosmic Origins Spectrograph with cospatial optical spectroscopy from the Very Large Telescope (VLT) Multi Unit Spectroscopic Explorer (MUSE) and the Large Binocular Telescope (LBT) Multi-Object Double Spectrograph (MODS). Our sample includes 18 YSCs spanning spectroscopic ages of ~1--6 Myr and galactocentric radii out to R/R₂₅ = 0.56. Neutral (H I) abundances were derived from UV absorption-line spectroscopy and compared with ionized (H II) abundances from reddening-corrected optical emission lines. Because auroral lines are not detected in all regions, we develop and apply an empirical multizone electron-temperature (T_e) calibration based on strong-line diagnostics to estimate T_e and derive reliable nebular abundances. We measure oxygen (O), sulphur (S), nitrogen (N), and iron (Fe) abundances, tracing enrichment from distinct nucleosynthetic channels. The α-elements (O and S) exhibit similar behaviour, consistent with enrichment by core-collapse supernovae, whereas Fe shows weaker variations, reflecting its delayed production by Type Ia supernovae. Nitrogen displays the largest phase offset (ionized--neutral), with enhancements of up to ∆N/H ~ 1.5 dex and ∆N/O > 1.5 dex in the ionized gas relative to the neutral phase, indicating localized enrichment by massive stars and inefficient mixing between gas phases on Myr timescales. While the ionized gas exhibits signatures of feedback-regulated chemical enrichment and large-scale abundance gradients, corresponding trends are weak or absent in the neutral gas, consistent with metals remaining largely confined to the immediate star-forming environment during the earliest stages of cluster evolution in a massive grand-design spiral.

The GECKOS survey: assembly history of the lenticular galaxy NGC 3957

First Author: Ding, Y.
Instruments: MUSE
ProgramIDs: 110.24AS
BibCode: 2026MNRAS.552g1634D

We analyse the assembly history of the edge-on lenticular galaxy NGC 3957 using deep integral-field spectroscopic MUSE data from the GECKOS survey. By applying a dust-corrected multi-Gaussian expansion and a population-orbit superposition model, we disentangle the galaxy's stellar kinematics, age, and metallicity. We dynamically decompose the galaxy and identify three distinct components: a dynamically cold main disc, a compact nuclear stellar disc (NSD), and a hot component. The NSD emerges as the youngest and most metal-rich component (

$t = 6.9 \pm 0.4$

Gyr;

$[Z/H] = 0.49 \pm 0.06$

dex), implying that the stellar bar is a long-lived structure that formed at least

$\sim 7$

Gyr ago. The main stellar disc is dynamically cold (

$\sigma _z \sim 20\mathrm{ -}30$

km s^-1), precluding any significant mergers over the last

$\sim 8$

Gyr, and exhibits a strong positive age gradient (younger inside, older outside) beyond the bar radius. Synthesizing these dynamical fossil records, NGC 3957 likely evolved as a `faded spiral' in a small-to-medium group environment. Its outer disc might passively fade due to mild gas starvation, while the bar fuelled prolonged central star formation. Comparison with lenticular galaxies in the Fornax cluster reveals that this combination of internal secular evolution and mild starvation produces `outside-in' fading signatures that could mimic the environmental stripping typically seen in dense clusters.

Reddening maps of the Magellanic Clouds using spectral energy distribution fitting of red giants

First Author: Netzel, H.
Instruments: VIRCAM
ProgramIDs: 179.B-2003
BibCode: 2026A&A...713A.201N

Context. Robust reddening maps of the Large and Small Magellanic Clouds (LMC and SMC) are crucial for a wide range of astrophysical studies, including the calibration of the cosmic distance ladder, investigations of stellar populations in low-metallicity environments, and the characterization of interstellar dust properties. Aims. We aim to construct reddening maps of the Magellanic Clouds using spectral energy distribution (SED) fitting and to investigate the impact of different stellar atmosphere models on the resulting maps. Methods. We combined optical (ugriz) photometry from the SMASH survey with near-infrared (YJK_s) photometry from the VMC survey for red giant branch (RGB) stars. We matched the observed SEDs to synthetic photometry derived from three atmosphere model grids. Results. Our maps cover 34.5 deg² of the LMC and 24.5 deg² of the SMC at 4 arcmin resolution. We find mean reddening values of E(B - V) = 0.076 ± 0.022 mag for the LMC and 0.058 ± 0.024 mag for the SMC. We find that employing different atmospheric models results in differences of up to 0.03 mag in the mean reddening. Canonical R_V values for the Magellanic Clouds (3.41 for LMC and 2.74 for SMC; Gordon et al. 2003, ApJ, 594, 279) provide results consistent with previous studies. Conclusions. We confirm a higher and more structured reddening in the LMC compared to the SMC, with 30 Doradus standing out as the dominant high-reddening region. Our results show that the absolute reddening scale depends on the choice of stellar atmosphere models, while the relative spatial structure of the reddening maps remains stable.

Localized Deviations from the CO─Polycyclic Aromatic Hydrocarbon Relation in PHANGS-JWST Galaxies: Faint Polycyclic Aromatic Hydrocarbon Emission or Elevated CO Emissivity?

First Author: Kim, Jaeyeon
Instruments: ALMA_Band_3, ALMA_Band_6, MUSE
ProgramIDs: 2013.1.00803.S, 2013.1.01161.S, 2015.1.00121.S, 2015.1.00782.S, 2015.1.00925.S, 2015.1.00956.S, 2016.1.00386.S, 2017.1.00392.S, 2017.1.00766.S, 2017.1.00886.L, 2018.1.01321.S, 2018.1.01651.S, 2018.A.00062.S, 2019.2.00129.S, 2022.1.01479.S, 099.B-0242, 097.B-0640, 098.B-0551, 0100.B-0116, 1100.B-0651, 095.C-0473, 094.B-0321, 094.C-0623, 2012.1.00650.S
BibCode: 2026ApJ..1001...67K

Polycyclic aromatic hydrocarbon (PAH) emission is widely used to trace the distribution of molecular gas in the interstellar medium, exhibiting a tight correlation with CO(2─1) emission across nearby galaxies. Using PHANGS-JWST and PHANGS-Atacama Large Millimeter/submillimeter Array (ALMA) data, we identify localized regions where this correlation fails, with CO flux exceeding that predicted from 7.7 μm PAH emission by more than an order of magnitude. These outlier regions are found in 20 out of 70 galaxies and are located in galaxy centers and bars, without signs of massive star formation. We explore two scenarios to explain the elevated CO-to-PAH ratios, which can either be due to suppressed PAH emission or enhanced CO emissivity. We examine PAH emission in other bands (3.3 and 11.3 μm) and the dust-continuum-dominated bands (10 and 21 μm), finding consistently high CO-to-PAH (or CO-to-dust continuum) emission ratios, suggesting that 7.7 μm PAH emission is not particularly suppressed. In some outlier regions, PAH sizes and spectral energy distribution of the radiation differ slightly from nearby control regions with normal CO-to-PAH ratios, though without a consistent trend. We find that the outlier regions show higher CO velocity dispersions (∆v_CO). This increase in ∆v_CO lowers CO optical depth and raises its emissivity for a given gas mass. Our results favor a scenario where shear along the bar lanes and shocks at the bar ends elevate CO emissivity, leading to the breakdown of the CO─PAH correlation. Future JWST spectroscopy and deep ALMA observations of CO isotopologues will provide critical tests of this scenario.

The efficient star-forming regions of stripped-envelope supernovae

First Author: Solar, Martín
Instruments: ALMA_Band_6, MUSE
ProgramIDs: 095.D-0172, 114.27G5, 60.A-9194, 0100.B-0116, 097.B-0640, 1100.B-0651, 094.B-0321, 2013.1.00243.S, 2013.1.01161.S, 2015.1.00902.S, 2015.1.00925.S, 2015.1.00956.S, 2017.1.00392.S, 2017.1.00886.L, 2018.1.00272.S, 2018.1.01651.S, 2018.A.00062.S, 2019.1.01305.S, 2021.1.00099.S
BibCode: 2026MNRAS.552g1615S

Massive stars (

$\ge 8\, \rm {M}_{\odot }$

) play a key role in shaping the interstellar medium of galaxies through stellar feedback. However, how these stars form and evolve before exploding as core-collapse supernovae (SNe) remains elusive. We compute for the first time the star formation efficiencies (SFEs) at the locations of hydrogen-rich (H-rich) SNe and stripped-envelope SNe (SESNe) to constrain their progenitor properties. We used VLT/MUSE and ALMA observations of

$\mathrm{H}~\alpha /\mathrm{H}~\beta$

and CO(2--1) emission lines to trace the components of the warm ionized gas and cold molecular gas, respectively. Both observations resolve individual

${\rm H\, {\small II}}$

regions and giant molecular clouds at spatial resolutions on cloud scales (

$\sim 100$

pc). These combined data allow us to compute the SFE from the star formation rate (SFR) and the molecular gas mass (

$M_{\rm mol}$

) as

$\mathrm{SFE}=\mathrm{SFR}/M_{\rm mol}$

. We find that SESNe explode in environments that are currently forming stars eight times more efficiently than those of H-rich SNe (higher SFR for SESNe with similar

$M_{\rm mol}$

). On one hand, this is consistent with the scenario in which the majority of SESNe are produced from very massive stars (

$\ge 20~\rm {M}_{\odot }$

) if the initial mass function is top-heavy. On the other hand, most of SESN progenitor channels are formed from interacting binaries (

$\le 20~\rm {M}_{\odot }$

) if an increased binary system formation rate is connected with turbulences and, in turn, with the boost to SFE. Then, an increased binary fraction could explain the enhanced H

$\alpha$

luminosities. In summary, SESNe preferentially occur in regions of intense, efficient star formation rather than simply higher gas content.

DiskMINT-GARDEN: Self-consistent Models to Estimate Disk Masses

First Author: Deng, Dingshan
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2012.1.00158.S, 2012.1.00422.S, 2012.1.00870.S, 2015.1.00192.S, 2015.1.00678.S, 2015.1.00686.S, 2015.1.01017.S, 2016.1.00311.S, 2016.1.00484.L, 2016.1.00629.S, 2016.1.00724.S, 2017.1.00069.S, 2017.1.00940.S, 2017.1.01404.S, 2017.1.01419.S, 2018.1.00689.S, 2018.1.00945.S, 2018.1.01055.L, 2019.1.01683.S, 2021.1.00128.L, 2021.1.01123.L, 2022.1.00485.S, 2022.1.00875.L, 2023.1.00334.S, 2024.1.01001.L, 2024.1.01212.L, 2025.1.00324.L
BibCode: 2026ApJ..1006..136D

We present DiskMINT-GARDEN, a grid of self-consistent models together with a fast, open source inference tool for disk masses. The grid is built on DiskMINT, a tool that couples hydrostatic disk structure, continuum/line radiative transfer, and a reduced CO chemical network including freeze-out, grain-surface conversion, and isotope-selective photodissociation. The DiskMINT-GARDEN model grid spans a large range of stellar mass (0.1─2.0 M_⊙), gas disk mass (10⁻⁵─10⁻¹ M_⋆), dust-to-gas ratio (0.003─0.1), and characteristic radius (10─300 au), and provides synthetic ALMA observables. We train a machine learning regression model to infer the disk mass, dust-to-gas mass ratio, and disk size from the dust continuum and C¹⁸O line observations. Applying DiskMINT-GARDEN to archival ALMA data of 34 disks, we find gas masses in good agreement with dynamical and HD-based estimates. Comparing our results with estimates from chemical modeling using DALI, we find that their need for large-scale elemental or CO depletion can be accounted for by grain-surface chemistry implemented in DiskMINT, with CO conversion to CO₂ being one of the main reactions. Therefore, extant data suggest little chemical processing due to disk evolutionary processes.

Accurate proper motions of the protostellar system VLA 1623-2417

First Author: Hernández-Garnica, Ricardo
Instruments: ALMA_Band_3, ALMA_Band_4, ALMA_Band_5, ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2011.0.00902.S, 2013.1.01004.S, 2015.1.00084.S, 2015.1.01112.S, 2016.1.01468.S, 2018.1.00200.S, 2018.1.00353.S, 2018.1.00388.S, 2018.1.00769.S, 2018.1.01089.S, 2018.1.01205.L, 2019.1.01074.S, 2019.1.01792.S, 2022.1.01734.S
BibCode: 2026MNRAS.551g1411H

We present a detailed astrometric analysis of the quadruple protostellar system VLA 1623-2417, deriving accurate absolute proper motions for components A, B, and W, as well as, for the first time, individual motions for the compact binary components of VLA 1623-2417 A (Aa and Ab). Our study combines 37 archival interferometric observations from the Atacama Large Millimeter/submillimeter Array (ALMA) and the Karl G. Jansky Very Large Array (VLA) at centimetre and millimetre wavelengths, supplemented with additional data from the Submillimeter Array (SMA) and the Berkeley--Illinois--Maryland Association (BIMA) millimetre array taken from the literature. Together, these data provide time baselines of

$\sim$

34.5 yr for component B,

$\sim$

32.5 yr for component W, and

$\sim$

11 yr for the individual components Aa and Ab. The relative proper motions of Aa/Ab indicate significant orbital motions, but cover too small a fraction of the orbit to provide a reliable mass estimate. The relative proper motions of W with respect to components A and B indicate that W is approaching A/B at a projected speed of 1-2 km s

$^{-1}$

. These inward motions are inconsistent with scenarios in which component W has been dynamically ejected from the VLA 1623-2417 system. Instead, we argue that W is either not bound to the A/B components or is moving on a highly inclined orbit.

Challenges in probing turbulent and magnetic support in cores: The W43-MM1 protocluster case study

First Author: Valeille-Manet, M.
Instruments: ALMA_Band_3, ALMA_Band_6
ProgramIDs: 2013.1.01365.S, 2015.1.01020.S, 2015.1.01273.S, 2017.1.01355.L
BibCode: 2026A&A...713A.149V

Context. Estimating the level of nonthermal support in cores is both challenging yet crucial for constraining the earliest stages of star formation and improving our understanding of the underlying physical processes. Aims. We aim to quantify the kinetic and magnetic support operating within the cores of the high-mass protocluster W43-MM1, and to test the simple assumptions behind the approximated virial theorem, which is used to interpret observations. Methods. We used ALMA 12 m molecular line observations of DCN (3--2), ¹³CS (5--4), and CH₃CN (5₃--4₃) to estimate the kinetic support. The plane-of-sky magnetic field strength (B_POS) was derived from ALMA 12 m dust-polarization observations using the Davis-Chandrasekhar-Fermi (DCF) method. The B_POS estimates were obtained in areas with a diameter of ~12 500 au (~2.3″, the three-beam scale of polarimetric observations), which ensures statistically meaningful measurements for the DCF analysis. These values were then extrapolated to core scales (~2500 au) using the density--field strength relation. Results. We derived kinetic support estimates for 45 cores (21 prestellar and 24 protostellar), of which 21 also have magnetic field support estimates. The velocity dispersions range from 0.34 to 4.48 km s^-1. The three-beam scale B_POS values span 1.1--22.5 mG, which extrapolate to 1.1--49.3 mG at the core scale. Using the virial theorem, we find 16 out of the subset of 24 cores with turbulence alone (~70%) to be stable against gravitational collapse. From the subset of 21 cores with both estimates, ten cores (~50%) appear to be magnetically supported against gravity when considering magnetic fields alone. Combining both estimates, 18 cores (~85%) are found with α_vir,B > 1. These numbers are unexpectedly high, especially for protostellar cores that are expected to be undergoing collapse. Conclusions. We conclude that the contamination of the measured linewidths by organized motions (of order 1--3 km s^-1 and consistent with previous observational studies), together with the omission of surface terms in the observational virial theorem, prevents us from accurately measuring the nonthermal support in cores. This highlights that any simplified framework of a virial analysis can introduce significant biases when assessing the physical support mechanisms within cores.

The dynamical environment of the high-mass star-forming region G28.288-0.364

First Author: Dey, Jyotirmoy
Instruments: ALMA_Band_3, ALMA_Band_6
ProgramIDs: 2019.1.00195.L, 2023.1.00467.S
BibCode: 2026A&A...713A.167D

Context. Massive stars form within deeply embedded dust cores, and the development of hypercompact and ultracompact H II regions characterizes their early evolution. Identifying and analyzing such regions is essential for understanding the physical processes that govern massive star formation and the transitions between early evolutionary stages. Aims. We investigate the physical and kinematic properties of the massive star-forming region G28.288--0.364 to constrain the evolutionary stages of embedded H II regions and the surrounding cores. Methods. We analyze multiwavelength observations, including uGMRT radio continuum data; archival continuum and radio recombination line data from the GLOSTAR-D survey; high-angular-resolution ALMA Band 3 radio recombination line and 1.36-mm dust continuum data from the ALMAGAL survey; and complementary molecular line tracers. We derive spectral indices, measure linewidths and velocities of the radio recombination line emission, identify compact dust cores using dendrogram analysis, and estimate their physical properties. Results. The radio continuum emission exhibits a positive spectral index (α = 0.39 ± 0.01), consistent with partially optically thick free-free emission. High-resolution observations resolve the ionized gas into two distinct components with physical sizes of ~0.06 pc. Their radio recombination line linewidths (~37 and 32 km s^-1, respectively) indicate that one component is in a transitional stage between hypercompact and ultracompact H II regions, while the other is more evolved. The 1.36-mm dust continuum data reveal five dust cores with surface densities consistent with the theoretical threshold for massive star formation. Conclusions. G28.288--0.364 hosts multiple compact H II regions and dense cores at different evolutionary stages, including a rare transitional object between the hypercompact and ultracompact phases. These results highlight the complex and sequential nature of massive star formation within clustered environments and demonstrate the importance of high angular resolution multiwavelength observations for resolving the early evolution of massive stars.

Physical and chemical conditions of molecular gas in NGC 1068: The nuclear feedback in the circumnuclear disk and starburst ring

First Author: Jia, Bin
Instruments: ALMA_Band_3, ALMA_Band_4, ALMA_Band_5
ProgramIDs: 2018.1.00321.S, 2018.1.01506.S, 2018.1.01684.S
BibCode: 2026A&A...712A.201J

Context. Molecular gas in galaxies is shaped by both star formation and active galactic nuclei. In NGC 1068, the circumnuclear disk and the starburst ring offer a nearby case to study these effects with many molecular tracers. Earlier work has shown strong outflow activity and complex chemistry, which motivates the use of methods that combine radiative transfer with time-dependent chemistry. Aims. Our aim is to map the physical conditions across the circumnuclear disk and the starburst ring of NGC 1068 and to test whether the nuclear outflow influences the molecular gas in the ring. We also examine whether the heating or the quiescent cloud scenario better matches the observations. Methods. We used archival ALMA observations obtained in bands 3, 4, and 5, covering molecular species including HCN, HCO⁺, HNC, CS, CN, and C₂H. All data cubes were convolved to a common resolution of 0.″8 and sampled into 56 pc hexagons with a signal-to-noise threshold of three. We performed hierarchical Bayesian inference that links a non-local thermodynamic equilibrium radiative transfer module (SpectralRadex) with chemical modeling. To make the analysis efficient, we replaced direct UCLCHEM calculations with a neural network emulator trained on a large model grid. Sampling was done with Nautilus. We also compared our results with previous studies that used RADEX and UCLCHEM for selected regions. Results. The emulator reproduces the UCLCHEM abundances with a low error and allows inference at modest computational cost. We find clear radial and azimuthal variations in gas density, temperature, column density, and cosmic-ray ionization rate. Toward the inner edge of the starburst ring, both physical properties and CO line profiles suggest that the gas there is highly disturbed. Conclusions. By coupling chemistry and radiative transfer within a hierarchical framework, and by using a neural network to speed up the chemical calculations, we obtained spatially resolved constraints on the physical conditions in NGC 1068. The radial gradients and the non-Gaussian CO profiles indicate that the nuclear outflow influences the inner part of the starburst ring. Observations at higher angular resolution would resolve the gas components that are blended within our 56 pc beam and clarify how the nuclear outflow disturbs the inner starburst ring.

Exploring the survivability of higher-order multiple protostellar systems - the case of VLA1623

First Author: Murillo, N. M.
Instruments: ALMA_Band_7
ProgramIDs: 2018.1.01089.S
BibCode: 2026MNRAS.551g1639M

Higher-order protostellar systems (

$\ge$

3 components) are commonly observed in the early stages of low-mass star formation. A persistent question in star formation and evolution is whether these higher-order protostellar systems survive as gravitationally bound systems or dissolve into binaries over time. We explore this question with a case study of the embedded quadruple protostellar system VLA1623 and its observational constraints, assuming that the components A1, A2, B, and W are gravitationally bound. Using N-body simulations, we run a grid of models considering gravity, mass accretion on to protostars, the presence of the protostellar cloud core, and its dispersal. The simulations are integrated over a period of 8 Myr to take into account the evolution from the protostellar phase (Class 0 and I, 1 Myr), through the pre-main sequence (Class II and III, 2--3 Myr), and into the main sequence (4 Myr). Our results show that VLA1623 has a probability of 30 per cent to remain as a gravitationally bound quadruple system up to 8 Myr from the current state. There is also a 25--30 per cent probability of VLA1623 dissolving into a triple system. This suggests that the dissolution of quadruple protostellar systems contributes to the formation of stable triple (proto)stellar systems. Components A1 and A2 are the most likely to be ejected, while W has a lower probability of being ejected from the system. The stability of VLA1623 depends on a combination of component mass ratios wrt the primary, separations, and eccentricities.

First Very Long Baseline Interferometry Fringe Detection at 690 GHz

First Author: Chen, Ming-Tang
Instruments: ALMA_Band_6, ALMA_Band_9
ProgramIDs: 2011.0.00014.E
BibCode: 2026PASP..138h4104C

We report the first very long baseline interferometry (VLBI) experiment conducted in the 690 GHz atmospheric window. On 2024 November 21, observations with the Atacama Large Millimeter/submillimeter Array, the Atacama Pathfinder EXperiment (APEX), and the James Clerk Maxwell Telescope (JCMT) were carried out using ALMA's newly developed Band 9 phasing capability. Fringes were detected on the ALMA─APEX baseline during a scan of the quasar J0423─0120, with a signal-to-noise ratio of ∼12 and useful fringe recovery over solution intervals of order tens of seconds, representing the highest-frequency ground-based VLBI fringe detection reported to date. No fringes were found on the ALMA─JCMT baseline, despite excellent weather conditions, consistent with sensitivity predictions and supporting baseline performance models. The ALMA Phasing System maintained stable phasing at Band 9 for ∼1─2 minutes before gradually degrading, indicating limitations under these observing conditions. Our analysis shows that, under excellent weather conditions, 690 GHz VLBI can still support fringe recovery over short solution intervals, despite rapid atmospheric phase fluctuations at these frequencies. This work validated key elements of near-terahertz VLBI operation and establishes a technical foundation for routine observations in the 690 GHz atmospheric window.

JWST Edge-on Disk Ice (JEDIce): Vibrationally Hot, Rotationally Cold H₂ in the Outer Disk of Oph 163131 Nonthermally Excited by Ultraviolet and Cosmic Rays

First Author: Assani, Korash
Instruments: ALMA_Band_6
ProgramIDs: 2018.1.00958.S, 2016.1.00771.S
BibCode: 2026AJ....172..170A

Constraining ionization and excitation processes in protoplanetary disks is essential for understanding the chemical structure and evolution of disk material, shaping planet formation pathways. We present JWST/NIRSpec integral-field-unit observations of the edge-on disk Oph 163131, which reveal an unusual rovibrational H₂ spectrum dominated by the 1─0 O(2) line (2.627 μm), with suppressed higher-J emission despite excitation to v = 2 and 3. This vibrationally hot, rotationally cold H₂ emission is spatially extended, broadly following the molecular disk traced by CO(J = 2─1), with emission increasing above and below a thin midplane dark lane and extending radially beyond ∼200 au, where near-IR scattered-light emission is no longer dominant. We interpret the observed H₂ emission as arising from nonthermal excitation in cold, dense outer-disk gas, where collisions depopulate higher-J rotational levels within each vibrational manifold prior to emission, producing the characteristic "v-hot, J-cold" spectrum. We consider both ultraviolet irradiation and cosmic-ray excitation as contributors to the H₂ emission and find that their combined action, together with collisional deexcitation of high-J level populations, broadly reproduces the observed line ratios and morphology. Within this framework, we infer a rather high effective cosmic-ray ionization rate of ∼(1─10) × 10⁻¹⁵ s⁻¹ in the presence of a moderate UV field (χ_UV = 100−1000, in Draine units). These results for disks, together with the recent findings by Bialy et al. for the lower-density starless core B68, highlight the potential of ro-vibrational H₂ emission as a novel probe of cosmic-ray ionization.

Old and Bright: The Remarkable Radio Brightening of the Engine-driven SN 2012au Several Years after Explosion Signals the Birth of a Pulsar Wind Nebula

First Author: Wiston, Eli
Instruments: ALMA_Band_3, ALMA_Band_7
ProgramIDs: 2019.A.00006.T
BibCode: 2026ApJ..1008...97W

We present the results from an extensive broadband (radio to X-rays) observing campaign of the engine-driven Type Ib SN 2012au in the first 13 yr of evolution. The early time (δt <= 190 days) radio and X-ray evolution is well described by conventional models of a forward shock interacting with a wind-like circumstellar medium (CSM; ρ_CSM ∝ r^-2). However, starting at δt ≈ 6.7 yr, we detect a significant radio rebrightening. This late-time emission is dominated by a luminous component characterized by a broad and rapidly evolving spectral peak and a shallow optically thin spectral slope, F_ν ∝ ν^{-0.31 ± 0.02}. These properties imply a compact emitting region (R ≲ 10¹⁶ cm) expanding at a remarkably slow velocity (v_s ≲ 500 km s^-1) into a high-density environment (n_e >= 10⁴ cm^-3), accompanied by a hard electron power-law index p ≈ 1.6. No soft or hard X-ray emission is detected at any epoch, indicating that high-energy radiation is either strongly absorbed or intrinsically absent. In the context of aspherical shock--CSM interaction models, these observations imply extreme properties of the CSM (geometry, density, and total mass) that lack clear astrophysical motivation. Instead, we show that the emergence of radiation from a newborn pulsar wind nebula (PWN) naturally explains the radio spectral evolution and high-energy limits, where the emission is governed by the adiabatic expansion of a relic pair plasma. We conclude that SN 2012au represents the most compelling candidate for a young, newborn PWN discovered to date, a scenario that can be directly tested with pending very long baseline interferometry observations.

Probing the Innermost Region of the V883 Ori Disk Using ALMA Band 1 Methanol Line Observations

First Author: Yamato, Yoshihide
Instruments: ALMA_Band_1, ALMA_Band_6
ProgramIDs: 2021.1.00186.S, 2024.1.01619.S
BibCode: 2026ApJ..1008..106Y

The snowlines of major volatiles in protoplanetary disks play a pivotal role in dust evolutions and volatile delivery to nascent planetary systems. In this paper, we report the Atacama Large Millimeter/submillimeter Array Band 1 (≈7.5 mm) observations of methanol (CH₃OH) emission lines in the disk around the FU-Ori type star V883 Ori, where accretion outburst heats the disk and the majority of ices have sublimated. We detect three CH₃OH emission lines at an angular resolution of ≈0.″2 . The stacked CH₃OH image exhibits a centrally-peaked morphology in contrast to the previous (sub-)mm observations that show a central depression. By fitting radially-resolved line profiles, we derive the radial intensity profile of the CH₃OH emission where we find a steep increase at ≲40 au. The column density of CH₃OH reaches at least ~10¹⁹--10²⁰ cm^-2 at ~10 au. This provides direct evidence that a significant amount of warm gaseous methanol is present in the innermost region of the disk where its emission has been suppressed in previous (sub-)mm observations due to the optically thick dust emission. The steep increase in the intensity profile may indicate that the CH₃OH snowline in the midplane is located at ~30--55 au, or that the CH₃OH emission traces the temperature structure given that the emission is likely optically thick. Our results demonstrate the capability and significance of (sub-)cm observations in probing the innermost opaque region of disks, paving the way for the future observations with upcoming facilities.

A Steep-extinction Quasi-stellar Object at z = 4.6: JWST Evidence for Abundant Small Dust Grains

First Author: Li, Mingyu
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2015.1.01074.S, 2012.1.00326.S
BibCode: 2026ApJ..1008L..22L

The rapid accumulation of massive dust reservoirs in the early Universe remains a major challenge in astrophysics. While core-collapse supernovae can inject large dust grains (a ≳ 0.1 μm) on short timescales, explaining the total dust budgets in the early Universe likely requires efficient grain growth in the interstellar medium (ISM). Such growth depends critically on an abundant population of small grains, which maximize the surface area available for accretion and may be generated by rapid dust-processing or dust-formation channels. Here, we report the discovery of a QSO, UDS-27023, at z = 4.556 ± 0.003, identified using JWST/NIRSpec spectroscopy. By quantitatively comparing the spectra to QSO composite templates, we find that UDS-27023 displays an exceptionally steep far-UV extinction curve (A₁₅₀₀/A_V ≈ 8) but notably lacks the 2175 Å bump (A_bump/A_V < 0.34 at 3σ), indicating a dominance of small silicate dust grains. We interpret this phenomenology as evidence for active small-grain production and processing in the QSO environment. Mechanical shattering of pre-existing large grains by QSO-driven shocks and outflows provides one natural pathway, while in situ condensation of silicate grains inside dense QSO-driven winds may offer an additional route. Such a population of steep-extinction QSOs (SEQs) may therefore reveal a short-lived phase in which luminous active galactic nuclei generate, process, and redistribute small grains, potentially facilitating rapid ISM grain growth and enriching the circumgalactic medium.

ALMA CO-CAVITY: I. Resolved molecular gas in void galaxies

First Author: Espada, D.
Instruments: ALMA_Band_3
ProgramIDs: 2022.1.00482.S
BibCode: 2026A&A...712A.227E

The environment plays a key role in galaxy evolution, yet it remains unclear how detailed molecular gas properties and their connection to star formation and stellar content are influenced by both large-scale and local environments. Here we introduce the ALMA CO-CAVITY project, the first interferometric CO(1--0) survey of a large sample of 41 void galaxies (VGs) to characterise in detail their molecular gas properties. It is built over the CAVITY project, offering optical integral field unit (IFU) data, enabling a direct, pixel-to-pixel comparison between molecular gas (from ALMA), star formation, and stellar properties, as well as the derivation of their scaling relations. In this work we present ALMA data products for our sample, containing data cubes, moment maps, and position-velocity diagrams at an angular resolution of 1″. We also present molecular gas, stellar mass, and star formation rate surface density maps at a common resolution of 2⋅^''5. We contextualise our sample against representative unresolved and resolved surveys. While our sample provides a good representation of the VG population and follows the distribution of key properties seen in star-forming galaxy samples, galaxies included in resolved studies from the literature tend to be more massive, less isolated, and located in denser large-scale environments. We present global scaling relations for the ALMA CO-CAVITY sample and find that the molecular gas main sequence exhibits the smallest scatter (0.21 dex), followed by the Schmidt--Kennicutt relation and the star-forming main sequence. From integrated properties alone, we find that these scaling relations for VGs are compatible with those for denser environments. This paper lays the foundation for forthcoming studies exploiting this unique dataset.

Magnetic fields in massive star-forming regions (MagMaR): VII. The dynamical importance of B-fields in the massive protocluster W33 A

First Author: Xu, F.
Instruments: ALMA_Band_3, ALMA_Band_6
ProgramIDs: 2018.1.00105.S, 2019.1.00685.S, 2017.1.00101.S
BibCode: 2026A&A...713A.145X

Our understanding of magnetic fields (B-fields) in massive star formation remains incomplete. Linear polarized emission from magnetically aligned dust grains provides a good way to map the morphology of the B-field on the plane of the sky. Here, we present the 1.2 mm full polarization observation of W33 A, a massive star-forming region at 2.4 kpc, obtained with the Atacama Large Mil-limeter/Submillimeter Array (ALMA) to achieve an angular resolution of ~0″.3 (~730 au). W33 A is resolved into 20 dense cores and nine filaments. It reveals various B-field structures, including two perpendicular large-scale components oriented northwest--southeast (NW--SE) and northeast--southwest (NE--SW), as well as two local distinct features toward the millimeter peaks MM1 and MM2. The NW--SE component could be shaped by a molecular outflow. The NE--SW one is remarkably coherent along the main filamentary structures (F1, F-Main, Tail), all with trans-Alfvénic turbulence. In F-Main, the line mass exceeds the turbulent critical limits, so magnetic support is required to prevent radial collapse and suppress local fragmentation. In F1 and Tail, turbulence is sufficient to support gravity, although B-fields can potentially provide additional support. Toward MM1, the fields follow a spiral-like, infalling streamer traced by CH₃CN; the inferred trans-Alfvénic turbulence in the accreting material indicates magnetic damping of turbulence and a magnetically regulated, laminar accretion flow that continues to feed the core. Toward MM2, the field exhibits an hourglass geometry described by parabolic curves. Two independent methods yield a consistently strong field strength of ~8.1 ± 1.9 mG. The virial analysis shows that the B-field can add 25% (75% from turbulence) support against gravity but is not by itself sufficient to halt collapse. Our study shows that within one protocluster, B-fields can both help stabilize gas filament against local fragmentation to facilitate mass accretion and delay gravitational collapse. The distinct evolutionary stages of MM1 and MM2 highlight the dynamic importance of B-fields in massive star formation.

ALMA-IMF: XXII. Role of core subfragmentation in the IMF origin: Hierarchical mass cascade in W43-MM1

First Author: Motte, F.
Instruments: ALMA_Band_3
ProgramIDs: 2019.1.00502.S, 2018.1.01787.S, 2017.1.01355.L
BibCode: 2026A&A...713A.105M

Aims. The gravoturbulent fragmentation of the interstellar medium is expected to create a hierarchical cascade of cloud structures, crossing the scales from core to disk. We aim to predict how the currently observed top-heavy core mass function (CMF) in the massive protocluster W43-MM1 evolves due to core subfragmentation. Methods. We used the getsf algorithm to extract sources in five ALMA images of W43-MM1 at 3 mm, with a spatial resolution ranging from 14 kau to 270 au. Then, we applied FAMILY, a graph-theory-based analysis tool, to create and characterize networks of nested sources in W43-MM1. We compared the hierarchical fragmentation cascade of W43-MM1 to those measured in the NGC 2264 protocluster and in synthetic images of an Orion-like protocluster simulated by magneto-hydrodynamical calculations. Results. Assuming self-similarity, we measured a small fractality index of F_3D = 1.19 ± 0.10 in W43-MM1, which means that, on average, a cloud structure fragments into only 1.19 fragments each time the physical scale decreases by a factor of two. In line with values measured above the core scale in the NGC 2264 and synthetic protoclusters, the W43-MM1 fractality index increases by about 30% at larger scales. We also estimate an imbalanced mass partition between siblings, with two-thirds of the mass of siblings at a given scale belonging to the dominant sibling. The mass transfer efficiency, computed from one physical scale to another, is high and corresponds to a core formation efficiency (CFE) from 2400 au cores to 200 au seeds of ~16%. Conclusions. Based on the fractality and efficiency values measured in W43-MM1, the gravoturbulent model by Thomasson predicts that its fragmentation below ~14 kau is not driven by turbulence but by gravity. Using these parameters and the measured mass partition, we demonstrate that the seed mass function, from which the initial mass function (IMF) emerges, has a high-mass end that remains top-heavy. Therefore, based on our current assumptions, core subfragmentation in W43-MM1, and perhaps more broadly in massive Galactic protoclusters, plays a minimal role in shaping the high-mass slope of the IMF.

Disk Evolution and Planet Formation in the Triple HD 104237 System

First Author: Hales, Antonio S.
Instruments: ALMA_Band_6
ProgramIDs: 2021.1.01137.S
BibCode: 2026ApJ..1009...41H

Planets are rare in close (a < 10 au) binaries, consistent with millimeter surveys showing that circumbinary disks in such systems are typically fainter than disks around wide binaries or single stars. However, a few bright circumbinary disks deviate from this trend, suggesting that planet-forming reservoirs can sometimes survive severe dynamical truncation. We present high-angular-resolution (0 .″ 1; 11 au) Atacama Large Millimeter/submillimeter Array Band 6 observations of the triple system HD 104237, a young Herbig Ae spectroscopic binary (a = 0.22 au) with a tertiary companion at 134 au in the ϵ Cha association. The data reveal a compact circumbinary dust disk with outer radius R_dust ≈ 8 au and a characteristic CO gas radius R_CO ≈ 18 au, with faint CO emission extending farther outward. Despite its small size, the disk remains relatively massive, consistent with the high stellar accretion rates observed in the system. Modeling the CO kinematics with a Markov Chain Monte Carlo fit to the visibilities yields a dynamical mass for the central binary of M_* = 2.42 ± 0.36 M_⊙, lower than previous estimates. The CO velocity field is well described by Keplerian rotation, with no significant residuals. Hydrodynamic simulations reproduce the observed disk truncation and velocity structure, indicating that the tertiary companion limits the outer disk. Nevertheless, a substantial gaseous reservoir persists within the compact inner disk, compatible with ongoing planet formation. HD 104237 is therefore an outlier to the general trend of disk depletion in close binaries, demonstrating that compact massive circumbinary disks can survive in dynamically complex multiple systems. We also report millimeter continuum and ¹²CO(2--1) emission from the disk surrounding HD 104237 E.

Nascent Embedded-protostar Survey in Taurus (NEST). I. Protostellar Multiplicity

First Author: Plante, Aislinn C.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2019.1.00847.S, 2016.1.01284.S
BibCode: 2026ApJ..1008..251P

We present new Atacama Large Millimeter/submillimeter Array (ALMA) 0.9 mm and Very Large Array (VLA) 9 mm observations in the Taurus Molecular Cloud (TMC) of 25 protostellar systems, containing 40 protostars, observed at 0 .″ 3 (~20 au) resolution. Within separations of 18--10,000 au, the ALMA/VLA-observed Taurus sample has a multiplicity fraction (MF), defined as the fraction of systems with at least one companion, of 0.50 ± 0.07, and a companion fraction (CF), defined as the average number of companions per system, of 0.58 ± 0.20. To build a more complete census of protostellar multiplicity in this region, we supplement the observed sample with 24 protostars (12 protostellar systems and five additional companions associated with systems we observed) previously identified through archival infrared or ALMA observations. Together, these 64 individual protostars (37 systems) define our Taurus+ sample, for which we measure higher values of 0.53 ± 0.06 and 0.72 ± 0.19 for the MF and CF, respectively. These multiplicity statistics in the TMC are notably higher than those reported in the more clustered star-forming regions of Orion and Perseus at the ~3σ--4σ level, suggesting that Taurus may preserve a larger fraction of primordial multiples. The separation distributions in our samples show populations of both close and wide multiples, but a deficit at intermediate separations of 200--300 au. This pattern may suggest two distinct formation pathways: close binaries (<200 au) arising primarily from disk fragmentation, and wide multiples (>1000 au) from core fragmentation.

SMA 200-400 GHz Survey for 10 Faint Class II Disks in the Taurus Molecular Cloud

First Author: Chung, Chia-Ying
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2016.1.01511.S, 2022.1.01302.S, 2021.1.00854.S, 2016.1.00715.S, 2013.1.00105.S
BibCode: 2026AJ....172..195C

We have performed Submillimeter Array (SMA) observations of 198.0--407.5 GHz broadband spectra of 10 Class II protoplanetary disks in the Taurus-Auriga region. The 337 GHz flux densities (F_{337 GHz}) of these objects are in the range of 8.2--34 mJy. The median and standard deviation of the 198--358 GHz spectral indices (α_198-358) of these 10 Class II disks are 1.9 and 0.3, respectively. Compared to the recent, similar SMA survey on another 47 Class II disks that are brighter in (sub)millimeter bands (F_{337 GHz} ~ 20--730 mJy), there is no evidence that these newly observed 10 fainter Class II disks have systematically different α_198-358 values. At >230 GHz frequencies, the optical depths of these 10 fainter Class II disks may be as high as those of the brighter sources, which may be ≳5. In addition, the low (<2.0) values of α_198-358 in some faint objects may be explained by the effect of dust self-scattering, with maximum dust grain size ( amax ) ~100 μm, or by contamination by free--free emission.

Emergence of high-mass stars in complex fiber networks (EMERGE): VI. Turbulence dissipation and the formation of dense fibers

First Author: Bonanomi, Francesca
Instruments: ALMA_Band_3
ProgramIDs: 2013.1.00662.S, 2019.1.00641.S, 2015.1.00669.S
BibCode: 2026A&A...713A..74B

Context. A turbulent cascade naturally generates a hierarchy of structures within molecular clouds. Filament networks arise from this turbulent cascade, with fibers suggested to be the first (tran)sonic components formed out of it. Consequently, the properties of cores forming within fibers may be inherited from the larger spatial scale of the filaments, where the dissipation of turbulence occurs. Aims. We aim to investigate the diffuse gas kinematics and its interaction with the dense gas composing fibers. We also aim to characterize the diffuse material via the HNC molecular tracer. Methods. We used high-resolution (4.5 arcsec or ~2000 au) large-scale ALMA+IRAM-30 m mosaics to survey five star-forming regions in Orion, as part of the EMERGE Early ALMA Survey. Our sample includes low- (OMC-4 South and NGC 2023), intermediate (OMC-3 and LDN 1641N) and high-mass (Flame nebula) star-forming regions, covering a wide range of stellar activity, cloud morphology, and evolutionary stages. We observed our targets in HNC (1--0) as probes of the diffuse gas in the regions and compared our findings to the N₂H⁺ (1--0) emission tracing the dense gas. We systematically investigated the emission of the diffuse gas in relation to the dense structures identified in N₂H⁺, focusing on its kinematics and velocity field. Results. The high resolution (2000 au) observations reveal that HNC traces lukewarm, diffuse (~5 × 10²¹ cm^-2) material around dense fibers. The properties of the diffuse gas appear to be similar across our sample, despite the wide range of different environments. We find that compared to the quiescent and subsonic gas inside fibers, the diffuse gas is more turbulent (ℳ^~_s = 2.9M~s=2.9). We observe the HNC nonthermal velocity dispersion to be roughly constant and homogeneous where the dense gas is detected (ℳ_s ~ 2), and rising along its edges up to ℳ_s ~ 5. Understanding the dissipation process is crucial marking the transition between the dense subsonic gas and diffuse turbulent material occurs. We investigated the turbulence dissipation through the statistical analysis of the HNC velocity gradients. While the majority of the gas shows ∇V_lsr <= 5 km s^-1 pc^-1 with roughly constant values, we identified high-shear regions showing higher gradients with ∇V_lsr >= 10 km s^-1 pc^-1 concentrated in small features of 0.1--0.3 pc in size located near the dense gas. Despite their small size, these high-shear structures appear to be major contributors of the turbulence dissipation in our targets. Conclusions. Our results suggest that in the case of Orion, the transition to coherence occurs at the fiber level. This interpretation is supported by the turbulence being effectively dissipated before the formation of cores and during the formation of these first dense gas structures.

Local constraints on alcohol-thioalcohol analogs in G35.2N

First Author: Xu, Xuefang
Instruments: ALMA_Band_6
ProgramIDs: 2021.1.00713.S
BibCode: 2026A&A...713A..67X

The chemistry of sulfur-bearing complex organic molecules in dense star-forming environments remains uncertain, partly because the dominant sulfur reservoirs in dense gas and ices are poorly identified. Alcohol--thioalcohol pairs provide a direct basis for comparing the abundance behavior of structurally related O- and S-bearing molecules. We present ALMA Band 6 observations of G35.2N and investigate the alcohol--thioalcohol pairs CH₃OH/CH₃ SH and C₂H₅OH/C₂H₅SH toward three selected spectral-extraction positions, MM3-pos, MM4-pos, and MM5-pos, in the MM3--MM5 region. Local thermodynamic equilibrium spectral modeling was used to derive molecular column densities and abundance ratios. The CH₃ OH column density was derived from ¹³CH₃OH by adopting ¹²C/¹³C = 50, because the main isotopologue is affected by optical-depth effects. Robust column-density constraints were obtained for CH₃OH, CH₃ SH, and C₂H₅OH at all three positions. C₂H₅SH was robustly constrained toward MM3-pos and MM5-pos but remains tentative toward MM4-pos. The adopted column densities vary moderately across the three positions, with ranges of (1.8-2.7) × 10¹⁸ cm^-2for CH₃OH, (1.7-2.6) × 10¹⁶ cm^-2 for CH₃SH, (5.7-8.5) × 10¹⁶ cm^-2 for C₂H₅OH, and (2.4-4.6) × 10¹⁵ cm^-2 for C₂H₅SH. Within the adopted uncertainties, the CH₃OH/C₂H₅OH and CH₃OH/CH₃SH ratios are consistent across MM3-pos, MM4-pos, and MM5-pos, with nominal values of 31--32 and 100--110, respectively. Comparison with other chemically rich sources and warm-up chemical models shows that the CH₃ OH/C₂ H₅ OH ratio in G35.2N lies within the range measured in other sources, whereas CH₃OH/CH₃SH shows a larger source-to-source variation. The ethyl-level O/S comparison remains less certain because many literature C₂H₅ SH measurements provide only lower limits. CH₃OH/CH₃SH is therefore the best-constrained O/S alcohol--thioalcohol analog ratio in the present data and provides a useful empirical probe of source-dependent sulfur-bearing organic chemistry, while higher-sensitivity C₂H₅SH observations are needed to test the C₂ H₅ OH/C₂ H₅ SH ratio.

A high-velocity SiO jet from S255N SMA3

First Author: Klaassen, P. D.
Instruments: ALMA_Band_6
ProgramIDs: 2023.1.01346.S
BibCode: 2026MNRAS.551g1645K

We present Atacama Large Millimeter/subillimeter Array (ALMA) Band 6 observations of the compact source SMA3 in the S255IR region, analysing both SiO (J = 5-4, 6-5) and CS (J = 5-4) emission to characterize the structure and kinematics of its outflow. The data reveal a highly collimated bipolar jet traced by SiO, reaching line-of-sight velocities of up to

$\pm$

60 km s

$^{-1}$

and deprojected velocities of

$\pm \sim$

80 km s

$^{-1}$

, with a collimation ratio of

$\sim$

4.7 over a spatial extent of

$\sim$

5800 au. The inferred dynamical age is 343 yr. Position--velocity diagrams exhibit a continuous velocity structure with triangular morphology, consistent with a steady disc wind rather than an episodic or X-wind-driven flow. Excitation analysis yields a characteristic SiO temperature of

$\sim$

42 K, and we derive the jet mass, momentum, and kinetic energy which are indicative of a dense, mass-loaded molecular outflow. The emission shows clear chemical and kinematic differentiation: SiO traces the high-velocity jet spine, while CS is observed at lower velocities close to the protostar, and only reaches high velocities at larger distances. Despite forming within a clustered high-mass star-forming region, the jet exhibits a high degree of symmetry, collimation, and dynamical coherence more commonly associated with protostars forming in isolation or less crowded star-forming regions. This demonstrates that well-ordered, narrowly collimated, disc-driven jets can be launched and maintained even in the dense, competitive environments characteristic of high-mass star formation.

A JWST, ALMA, and VLA Survey of the Ophiuchus A Star-forming Region: Unveiling Hidden Dust Mass and Connecting Infrared Outflows to Their Radio Origins

First Author: Radley, Isaac C.
Instruments: ALMA_Band_6
ProgramIDs: 2017.1.00107.S, 2019.A.00034.S
BibCode: 2026AJ....172..190R

We present an infrared, millimeter, and radio survey of 20 Class 0--III young stellar objects in the Ophiuchus A L1688 star-forming cluster, combining high-resolution (7--25 au) Very Large Array (VLA) and James Webb Space Telescope observations with archival Atacama Large Millimeter/submillimeter Array data. We implement physically motivated models to derive dust and ionized gas properties, spectral behaviour, and their relative contributions through the millimeter-to-centimeter radio spectral energy distribution. Our models reveal circumstellar dust disks that are, on average, tens to hundreds of times more massive than millimeter-only estimates (subject to uncertainties arising from the choice of dust opacity) and contain millimeter-sized grains even at the Class 0 stage. Owing to the VLA's high resolution, we are able to connect outflows to their origins, detecting protostellar jet emission on scales of tens to thousands of au. Our results represent a homogeneous characterization of the dust and ionized gas properties in Ophiuchus and present a potential solution to the long-standing ``missing disk mass'' problem. However, our understanding is still limited by resolution and sensitivity at frequencies <40 GHz. Future facilities like the Square Kilometre Array and ngVLA are needed to provide the necessary capabilities to fully spatially resolve this emission (< 0 .″ 18) even in one of the closest star-forming regions.

Multiband ALMA polarimetry of the jet base and kiloparsec-scale jet of 3C 273: A multicomponent Faraday structure in the nucleus

First Author: Hovatta, T.
Instruments: ALMA_Band_4, ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2018.1.00357.S
BibCode: 2026A&A...712A.244H

Aims. Polarization observations at millimeter wavelengths can be used to study magnetized plasma in jets launched by supermassive black holes. We used multiband Atacama Large Millimeter Array (ALMA) data to study the polarization structure of both the nucleus and the kiloparsec-scale jet of the archetypal quasar 3C 273. Methods. We modeled the wavelength-dependent polarization of the nucleus using multiband observations (2, 1.3, and 0.85 mm) and applied QU-fitting to constrain Faraday rotation models with one or more polarized components. We also produced total intensity and polarization maps of the kiloparsec-scale jet to study the evolution of the magnetic field structure along and across the jet. Results. The data of the nucleus were best fit by two Faraday components: a high rotation measure (RM) component with RM = +(2.6 ± 0.1) × 10⁵ rad m^-2 and comparable RM dispersion, and a second component with RM = +(1.5 ± 0.2) × 10⁴ rad m^-2 and lower dispersion. The high RM is comparable to previous ALMA observations at 1.3 mm, although we found clear evidence of variability when compared to previous single-band ALMA studies, highlighting the importance of broad wavelength coverage. On kiloparsec scales, the millimeter polarization structure closely resembled that observed at centimeter wavelengths, revealing a complex magnetic field configuration around the jet head and brightest hotspot region. Conclusions. Our results indicate a multicomponent, time-variable Faraday screen in the nuclear region of 3C 273 that is likely associated with a dense, magnetized environment close to the jet base. Future spatially resolved millimeter polarimetry with the Event Horizon Telescope will be crucial to disentangling these components and directly localizing the high-RM emission region.

From filaments to the hub: Gas kinematics and massive star formation in G329.34+0.14

First Author: Zhang, Wenjun
Instruments: ALMA_Band_3, SHFI
ProgramIDs: 193.C-0584, 092.F-9315, 2019.1.00685.S
BibCode: 2026A&A...713A..83Z

We present ¹³CO (J=2--1) emission from the SEDIGISM survey, together with ALMA Band 3 and Band 6 observations from the ATOMS and QUARKS surveys, to investigate the gas kinematics and feedback processes in the massive hub-filament system G329.34+0.14 (hereafter G329). Based on Herschel continuum morphology together with the ¹³CO (J=2--1) integrated intensity and velocity distributions, a parsec-scale network of filaments was identified, converging toward the hub that hosts two massive clumps, MC 1 and MC 2, with respective masses of ~4210 (±1259) M_⊙ and ~1483 (±443) M_⊙. Position-velocity analysis reveals systematic projected velocity gradients along the filaments, consistent with organized gas motions on parsec scales and possible inflows toward the hub. Within MC 1, ALMA resolves a sub-parsec network of intra-hub filaments (IHFs) traced by H¹³CO⁺ (J=1--0), with a velocity organization similar to that seen on parsec scales. These IHFs are distributed around a central H II region, surrounded by a shell-like structure traced by CS (J=2--1) and H¹³CO⁺ (J=1--0) emission, with dense gas concentrated in its northeastern and southwestern sectors. The shell further shows SiO (J=2--1) and SO (J=3(2)--2(1)) emission, excited mainly by low-velocity shocks from the expansion of the H II region, with a minor contribution from protostellar outflows. Compared with the surrounding parsec-scale filaments, the IHFs are more compact but exhibit larger velocity gradients and line masses, suggesting that the inner hub gas is denser and dynamically more complex. MC 1 and MC 2 are interpreted as two massive clumps embedded in the same hub, with MC 1 appearing more evolved and more strongly affected by feedback than MC 2. G329 therefore provides an observational case in which the parsec-scale hub-filament structure and the dense IHF network show a broadly similar velocity organization. This suggests a possible kinematic connection between the surrounding filaments and dense gas in the hub interior.

The low-mass companions in eclipsing binaries with F/G primaries: a large sample analysis

First Author: Cakirli, O.
Instruments: HARPS, NIRPS
ProgramIDs: 106.212H, 112.25KP, 113.26NT, 112.25UD, 115.27V0, 1101.C-0721, 092.D-0261, DataDoiProID
BibCode: 2026MNRAS.551g1625C

We present the absolute and orbital parameters of eleven very-low mass stars in eclipsing binaries, featuring F/G/K primaries and M dwarf secondaries, all positioned within the fully convective regime (M

$_*$

< 0.35

$\mathrm{M}_{\odot }$

) and down to the hydrogen burning mass limit (MHB

$\sim$

0.07

$\mathrm{M}_{\odot }$

). They show orbital periods exceeding several days, enabling us to explore the differences between observed and theoretical temperatures and radii. Our analyses, based on high-precision space photometry and enhanced by optical and infrared spectroscopy, yield measurements that closely match stellar evolution models. We suspect a slight systematic inflation in the radii of low-mass stars are likely due to observational errors, when compared to model predictions in the fully convective low-mass regime. The vital role of these results lies in their proof that low-mass eclipsing binaries provide an important chance to determine empirical masses and radii for these stars. In the end, our findings contribute eleven remarkable observations to the mass--radius diagram of fully convective M-dwarfs.

A catalogue of high angular resolution and contrast polarimetric maps of 45 nearby AGB stars with SPHERE/ZIMPOL

First Author: Badolo, Nekolgne Aymard
Instruments: SPHERE
ProgramIDs: 097.D-0516, 096.D-0930, 096.D-0252, 095.D-0309, 0100.D-0737, 098.D-0731, 0104.D-0240, 0103.D-0772, 099.D-0600, 098.D-0200, 097.D-0443, 098.D-0206, 097.D-0352
BibCode: 2026A&A...713A..56B

Aims. We present the largest catalogue of asymptotic giant branch (AGB) stars, 45 targets in total, observed in polarized light at high angular resolution (~20 milliarcsec). The main goal of the study is to detect and characterize dust shells in the close environment of nearby AGB stars. This work also aims to systematically classify the AGB star circumstellar morphologies obtained with the SPHERE instrument installed at the Very Large Telescope (VLT), thanks to its Zurich Imaging Polarimeter (ZIMPOL). Methods. We extracted and analyzed polarized intensity maps for 45 AGB stars, constructed from polarimetric observation data obtained with the SPHERE/ZIMPOL instrument. An ellipse fitting method was applied to characterize the circumstellar envelopes. Stellar parameters (luminosity, effective temperature, surface gravity, extinction, metallicity) were compiled and recalculated when necessary from spectral energy distribution (SED) fitting using the Python SED fitting tool (PySSED) software. These data were then used to train a random forest machine learning model to determine the most discriminating variables for a resolved envelope around a given star. Results. We constructed polarization maps for all stars in the sample, revealing a wide diversity of circumstellar morphologies. We detected 16 dusty circumstellar envelopes, including three never observed before. They display a wide range of morphologies, all of them showing a clear departure from spherical symmetry, indicating interaction with a companion or asymmetric mass ejections. The random forest model identified optimal thresholds for several physical parameters, thus providing robust criteria to anticipate SPHERE's ability to resolve dust envelopes around AGB stars. These results facilitate the selection of targets for future observations and contribute to a better understanding of the evolution mechanisms of circumstellar envelopes.

Constraining the orbit of the retrograde planet in the ν Octantis system

First Author: Signor, Alan Cefali
Instruments: HARPS
ProgramIDs: 0101.C-0232, 0103.C-0548, 0100.C-0414
BibCode: 2026A&A...712A.247S

The ν Octantis system is composed of a compact stellar binary and a retrograde S-type planet orbiting near the edge of stability. Here, we investigate the dynamically viable architectures of this system by exploring the planetary orbital elements with a Monte Carlo method. To handle the large number of free parameters, we employed a novel approach in which all relevant orbital parameters were varied simultaneously, which we refer to as corner stability maps. Furthermore, since the osculating orbital period of the planet undergoes large oscillations, we combined these maps with frequency analysis to identify the stable configurations that remain consistent with the observational data. We find that the retrograde planetary orbit most likely lies in the region of influence of the high-order 28/--11 mean-motion resonance, where its long-term stability is enhanced by secular apsidal alignment.

A Comprehensive Study of Morphology and Kinematics in Extended Nebulae Around UV-luminous Quasars at z ≈ 1

First Author: Liu, Zhuoqi (Will)
Instruments: MUSE
ProgramIDs: 096.A-0222, 094.A-0131, 0104.A-0147
BibCode: 2026ApJ..1008..247L

Gas flows between galaxies and the circumgalactic medium (CGM) play a central role in galaxy evolution and can become observable as giant nebulae when illuminated by quasars. We present an ensemble study of nebulae around 30 UV-luminous quasars at z ≈ 0.4--1.4 from the CUBS and MUSEQuBES surveys, 27 of which are detected in extended [O II] and/or [O III] emission. Based on a joint analysis of nebular morphology and surrounding galaxy environments, we introduce three morpho-kinematic classifications. We identify eleven irregular, large-scale (>50 kpc) systems, many of which are likely interaction-related; twelve compact host-galaxy-scale nebulae, likely tracing CGM/interstellar medium (ISM) gas; and four systems with complex morphologies of uncertain origin. We introduce a quantitative measure of the spatial and kinematic association between nebulae and quasar-host group galaxies, finding a statistically significant association for ten nebulae, most of which are irregular, large-scale nebulae, consistent with qualitative analysis. Radio jets are detected in six systems, with no strong correlation found between radio activity and nebular emission. The [O II] nebulae are more asymmetric than their Lyα counterparts at z > 2, but bear more similarity to H I gas observed in 21 cm around local elliptical galaxies. Blueshifted--redshifted patterns, likely tracing gas rotation, are observed in roughly 30% of the systems, though disturbed kinematics suggest that feedback may also be important. These results show that giant quasar nebulae are not a uniform class of objects, but instead arise through multiple pathways shaped by host-galaxy gas, galaxy interactions, group environments, and quasar activity, with the most striking cases associated with galaxy interactions.

The Galactic centre G+0.633-0.0604 molecular cloud: A new astrochemical gold mine: I. Gas physical properties

First Author: San Andres, D.
Instruments: nFLASH
ProgramIDs: 0109.F-9309
BibCode: 2026A&A...713A.102S

Context. In the central molecular zone (CMZ) environment, shocks play a key role in both triggering star formation and providing chemical enrichment. The Sgr B2 complex is a prime template, hosting several massive protoclusters (N, M, and S) and the northern G+0.693 cloud, which exhibits shock-induced prestellar signatures. Aims. We report on G+0.633-0.0604, a new shock-dominated and chemically rich cloud at the southern edge of Sgr B2, where it has been proposed that the next star formation episodes will occur. We characterise its physical properties and the shocks shaping it. Methods. We analysed data from new high-sensitivity broadband spectral surveys using the Yebes 40m, IRAM 30m, and APEX radio telescopes, covering a ~ 100 GHz aggregated bandwidth across the ~31-275GHz range. We present analyses of CH₃CCH, CH₃CN, HC₃N, HNCO, and several isotopologues of CO to infer kinetic temperatures and H₂ densities. We complementarily used 3 mm IRAM 30m mosaics (~13'×13', ~32×32 pc²) of Sgr B2 in HC₃N, HNCO, and C₂H₅OH to probe G+0.633's environment. Results. We identify three velocity components towards G+0.633: a narrow main one (C1, v_LSR~48.5 km s^-1; FWHM~10km s^-1) and two broader, much fainter components at higher velocities, C2 (~61 km s^-1; ~13km s^-1) and C3 (~89km s^-1; ~18km s^-1), all of which show similar properties (T_kin~55-90K, N_H₂~(3-7)×10²² cm^-2, n_H₂~(0.5-2.5)×10⁴ cm^-3) and extended distributions. C1 delineates G+0.633 physically, and corresponds to a peak in HNCO. This supports a shock-driven origin, likely rooted in the cloud--cloud collision shaping Sgr B2 and also traced by C2, which mainly extends north to G+0.693. C3 is kinematically unlinked and related to large-scale CMZ dynamics. Of the three, C1 may be consistent with a very early protocluster phase, but this is yet to be confirmed. Conclusions. G+0.633 emerges as a new shock-dominated CMZ cloud with a physical resemblance to G+0.693, providing another unique laboratory to investigate how shocks drive molecular complexity and regulate the onset of cluster formation in the CMZ.

Investigation of high-quality spectra of a sample of high-radial-velocity stars

First Author: Alazzawi, J. M. K.
Instruments: UVES
ProgramIDs: 079.B-0515
BibCode: 2026A&A...713A..60A

Context. Old, metal-poor stars are perfect tracers of the formation of the Milky Way. The combination of chemical and kinematic investigations into them provides an insight into accretion episodes in the past history of our Galaxy. Aims. We present here a detailed chemical abundance analysis of 16 metal-poor stars, selected from the RAVE survey, which are characterised by a high radial velocity. Methods. We derived stellar parameters from Gaia photometry and parallaxes. Using high-resolution spectra obtained with UVES at the ESO-VLT, we determined elemental abundances for α-, iron-peak, and neutron-capture elements using the MYGISFOS pipeline. Departures from local thermodynamic equilibrium, where available, were investigated. We used the SPInS bayesian inference pipeline to derive ages for all the stars. Actions and other dynamical quantities were computed using the galpy pipeline applying the Galactic potential MWPotential2014, in order to classify the stars kinematically. Results. The stars span a wide metallicity range (-1.2 ≲ [Fe/H] ≲ -2.9) and exhibit kinematic properties consistent with the outer halo population. Star C0213360--505024, [Fe/H]=-1.4, appears to have an age of 1.3 Gyr and a mass of 1.6 M_⊙. Based also on its kinematics and line broadening, which we attribute to stellar rotation, we argue that this star is young and not an evolved blue straggler. The available evidence points towards an accreted origin for this star and we speculate about its possible progenitor. The other 15 stars have ages compatible with an old population.

Gaps and rings: a near-universal trait of extended protoplanetary discs

First Author: Bosschaart, Q.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2016.1.01511.S, 2021.1.00854.S, 2022.1.00646.S, 2022.1.01302.S, 2023.1.01276.S
BibCode: 2026A&A...708A.143B

Context. Substructures such as rings, gaps, and cavities are commonly observed in protoplanetary discs and are thought to play a key role in dust evolution and planet formation. However, a fraction of the extended discs (68% dust radii >30 AU) in nearby star-forming regions remain unresolved, leaving their substructure content uncertain and thereby limiting our understanding of dust evolution and the initial conditions for planet formation across the full disc population. Aims. We aim to investigate the presence of substructures in previously unresolved, extended discs to assess whether all extended protoplanetary discs in the solar neighbourhood exhibit substructures. This enables a statistical evaluation of substructure occurrence among protoplanetary discs and provides statistical constraints for disc evolution models and comparisons with exoplanet populations. Methods. We present new high-resolution (∼0.12^'') ALMA (Atacama Large Millimeter/submillimeter Array) Band 6 continuum observations at 1.33 mm of 26 previously unresolved, extended discs within 200 pc. This completes the sample of high-resolution observations of extended discs in the nearby star-forming regions Taurus, Ophiuchus, Chamaeleon, Lupus, Upper Scorpius, Upper Centaurus-Lupus, and Lower Centaurus-Crux. We analysed radial intensity profiles using Frankenstein and Galario to detect substructures. Results. Seventeen discs show clear substructures, while nine appear compact and structureless, smooth, or ambiguous due to inclination or possible binarity or late-stage infall. We detect ¹²CO J=2-1 emission in 15 discs, where extended CO emission is observed in four discs. Combined with literature data, our complete sample of 730 protoplanetary discs reveals that nearly all extended discs exhibit substructures, ∼91% detected in the full sample, and up to ∼98% when correcting for high-inclination systems where substructures may be hidden. Conclusions. Substructures are a near-universal feature of extended protoplanetary discs. Substructures are more commonly detected and, it is proposed, more prevalent in larger, massive discs and around higher-mass stars, and structured discs retain their dust mass over time. This is consistent with the hypothesis that dust traps, possibly induced by giant planets, are key in shaping the dust disc morphologies.

Revised orbital parameters of the γ² Velorum system

First Author: Schmutz, Werner
Instruments: GRAVITY
ProgramIDs: 112.25Z3
BibCode: 2026A&A...713A..71S

Context.γ² Velorum is the closest and visually brightest Wolf-Rayet (WR) binary system. Its eccentric orbit modulates the X-rays observed from the wind-wind interaction, and its large separation enables spatial resolution of both components. Aims. We aim to strengthen the constraints on the properties of γ² Velorum and, in particular, to resolve the discrepancy between the eccentricity determined from the emission lines and that from the absorption lines. Methods. We obtained VLT/GRAVITY observations and combined them with earlier spatially resolved data covering different orbital phases. Results. We determine strong constraints on all orbital parameters and find that e = 0.322, close to the value derived from the emission lines. The X-ray light curve declines as s^-3 after periastron, where s is the separation of the two stars, but its modulation is likely affected by absorption and occultation of the X-ray emitting region at other orbital phases. We find that previous discrepancies in the reddening value can be traced to a brighter K-band magnitude than predicted by the WR wind models. We derive E(B - V) = 0.02 ± 0.02 mag. Our more precise mass and radius values, combined with previously determined effective temperatures, provide strong constraints on evolutionary models. The closest match for the O star comes from a rotationally mixed model with initial mass M_init = 28.7 M_⊙ and an M_init = 32 M_⊙ model for the WR star, with negligible accretion onto the O star during the WR progenitor's Roche lobe overflow phase. However, the temperature of the O star is higher and the mass of the WR star is smaller than predicted by the evolutionary tracks at the current epoch, consistent with the well-known ``mass-discrepancy problem'' in massive stars. Conclusions.γ² Velorum's strongly constrained parameters make it ideal for testing structure, evolution, and stellar wind models. ★ Based on observations collected at the European Southern Observatory under ESO program 112.25Z3.001.

Southern massive stars at high angular resolution: WR 25 is a massive hierarchical triple system

First Author: Deshmukh, K.
Instruments: PIONIER
ProgramIDs: 0102.D-0234
BibCode: 2026A&A...713A.108D

WR 25 is a massive colliding-wind binary in the Carina nebula comprising a WN6ha primary star with an O5 companion in an eccentric 208-day orbit. Recent spectroscopic analysis estimates the total binary mass to approach 100 M_⊙, and a primary-to-secondary mass ratio of q = M₁/M₂ ≈ 2, hinting at a very massive primary star. The presence of additional spectroscopic signatures from a third, ``intruder'' star was also noted, making it a candidate hierarchical triple system. In this study, we present a VLTI/PIONIER interferometric observation of WR 25, spatially resolving all three components for the first time. For the inner WN6ha + O5 binary, we find a projected angular separation of 1.68 ± 0.02 milliarcseconds (mas), corresponding to a projected physical separation of 3.90 ± 0.21 au at a distance of 2.32 ± 0.12 kpc. Leveraging the fortunate timing of the VLTI observation, which was obtained when the two components were passing the line of nodes, we determined the orbital semi-major axis a = 3.11 ± 0.20 au. Subsequently, the newly constrained total dynamical binary mass is 93 ± 18 M_⊙, with a primary mass M₁ = 62 ± 13 M_⊙ and secondary mass M₂ = 31 ± 7 M_⊙. We detect the third star or tertiary with a projected angular separation of 27.69 ± 0.02 mas from the primary, with a chance alignment probability lower than 10^-4. Using newly obtained brightness ratios between all components, we revisit archival spectroscopic data of WR 25 to disentangle spectra for individual components and derive their stellar parameters. The tertiary, which has a spectral type O7, is broadly coeval with the inner binary and has an evolutionary mass M₃ = 25.6_-2.3^+2.8 M_⊙ M 3 = 25 . 6 - 2.3 + 2.8 M ⊙ . Based on simulations, we estimate the tertiary period to be in the range 19--82 years. The newly confirmed triple nature of WR 25 thus makes it an important benchmark system to measure accurate dynamical masses of the inner binary and potentially the tertiary, to calibrate stellar evolution and atmosphere models, and to study its formation and stability as a hierarchical triple system.

Ongoing magnetospheric accretion in the multiring transitional disc of HD 141569A

First Author: Bakis, Volkan
Instruments: UVES
ProgramIDs: 079.C-0789
BibCode: 2026MNRAS.551g1441B

We present the results of long-term spectroscopic monitoring of the Herbig Ae star HD 141569A. The analysis is based on spectra obtained at the Shamakhy Astrophysical Observatory during 2017--2023 together with archival Ultraviolet and Visual Echelle Spectrograph spectra acquired with the European Southern Observatory Very Large Telescope in 2007. Using synthetic model atmospheres, we investigated the emission structure of the hydrogen Balmer lines in the presence of strong photospheric absorption. The H

$\alpha$

and H

$\delta$

emission profiles exhibit double-peaked structures with central depressions, indicating that the emitting gas is in Keplerian rotation within the circumstellar disc. Peak velocities were used to estimate the emission radii of several hydrogen lines. We find an increase in the linear gas velocity together with a gradual decrease in the peak intensity ratio (

$I_{\rm V}/I_{\rm R}$

) from the outer to the inner disc regions. The Na I D, Ca II K, and metallic absorption lines reveal outflowing gas with a velocity of approximately

$-13\pm 1.5$

km s

$^{-1}$

. Their narrow widths, significantly smaller than the stellar rotational velocity, suggest formation within an optically thick circumstellar wind. The hydrogen, Na I, and He I

$\lambda 5876$

lines show spectroscopic signatures of ongoing accretion onto the star. Accretion rates derived from the H

$\gamma$

and H

$\delta$

lines yield the most reliable lower limit to the mass accretion rate,

$\dot{M}_{\rm acc}\approx (0.85\!-\!0.93)\times 10^{-8}\, M_\odot \, {\rm yr}^{-1}$

. These findings demonstrate that magnetospheric accretion onto HD 141569A remains active despite its highly evolved multiring transitional disc.

VLTI/MATISSE observations of the hot dust around β Pictoris Observing faint objects with MATISSE

First Author: Priolet, P.
Instruments: MATISSE
ProgramIDs: 106.21Q8, 110.246D
BibCode: 2026A&A...713A..51P

Context. Hot exozodiacal dust has been detected in approximately 20% of nearby main-sequence stars, indicating that it is a common feature in extrasolar planetary systems. However, their spatial distribution and grain properties remain poorly understood. Aims. We aim to show that the spatial distribution of hot dust around β Pictoris -- an iconic planetary system with two known planets and a population of exocomets -- can be effectively constrained through a detailed analysis of optical long-baseline interferometry data. Methods. We obtained L-band (λ ~ 3.5 μm) observations of β Pictoris with the MATISSE instrument at the VLTI. We first developed a method to assess correlations in the visibility measurements by estimating the full data covariance matrix. We then modeled the circumstellar emission using geometric brightness distributions to fit the observed visibilities. Results. This study reveals circumstellar emission around β Pictoris consistent with hot exozodiacal dust. By modeling the emission both accounting and not accounting for correlations in the data, we demonstrate their significant impact on the inferred dust properties. The best-fit model reveals a compact (~0.05 au), highly inclined dust structure near the sublimation radius, misaligned by ~60° on the sky plane with respect to the extended edge-on outer disk, contributing ~4% -- 7.5% of the total flux at λ = 3.4 μm, and is composed of submicron-sized grains. The data are also compatible with an additional dust component near 1 au. Conclusions. In the case of β Pictoris, the two-decade-old paradigm -- placing hot exozodiacal dust near the sublimation radius and composed of submicron-sized grains -- finds observational support in the detailed analysis of MATISSE data. The misalignment with the known debris disk further supports a link to the exocometary activity.

Molecular gas and star formation in GASP jellyfish galaxies

First Author: Moretti, A.
Instruments: ALMA_Band_3, ALMA_Band_6, MUSE
ProgramIDs: 196.B-0578, 2017.1.00496.S
BibCode: 2026A&A...708A.125M

Context. Several studies have reported a nearly linear correlation between the molecular gas and star formation rate surface density, the so-called Kennicutt-Schmidt (KS) law. Aims. We aim to retrieve the KS relation for a sample of four star-forming galaxies located in nearby clusters, disturbed by the effects of the ram pressure stripping, as testing this law in galaxies subject to different environmental conditions can provide key information on the physics of star formation. Methods. To perform our analysis, we used ALMA band 6 and band 3 data coupled with MUSE data at spatial resolution of ∼1 kpc. Moreover, we analyzed data of star-forming complexes detected through their Hα ionized gas emission. We also derived the star formation efficiencies of the star-forming regions nested in these big complexes using the star formation rates derived from spatially resolved HST images and various recipes for the corresponding cold gas phase. Results. We find that ram-pressure-stripped galaxies show normal-to-low star formation efficiencies, depending on the position within the galaxy and on the local gas density: the inner dense regions in the disk show higher efficiencies with respect to the outer regions, including the gaseous tails. The global relation between the star formation rate density and the molecular gas surface density is superlinear, likely suggesting the shortening of the depletion times at high gas mass densities caused by the ram pressure. Within the star-forming complexes, the star formation efficiency is very similar to the one observed at 1 kpc scale in undisturbed star-forming disks. Interestingly, this result holds also for the star-forming complexes located in the stripped gas tails. The analysis of HST resolved clumps suggests that the molecular gas is not uniformly distributed within the star-forming complexes, but its density distribution follows a steeper profile.

Optical observations of candidate host galaxies of eight fast X-ray transients

First Author: van Hoof, Agnes P. C.
Instruments: FORS2, XSHOOTER
ProgramIDs: 113.26ET, 111.24P0
BibCode: 2026A&A...713A..63V

Context. Fast X-ray transients (FXTs) are extragalactic flashes of X-rays with a typical duration of minutes to hours for which a variety of origins has been proposed and observed. Aims. To decipher the origin of FXTs, particularly those lacking multi-wavelength counterparts, we aim to understand their energetics and environments. Methods. We present deep, optical ground-based observations of the positions of eight FXTs in order to try and identify and characterise candidate host galaxies. We used their properties to discriminate between possible progenitor scenarios. Results. We identify candidate host galaxies for Swift J050400.2+673405, XRT140507, XRT040610, XRT151121, XRT191127, and EP240708a. For each candidate, we infer the spectroscopic or photometric redshift, stellar mass, star formation rate, metallicity, and stellar population age by fitting our data with the spectral-energy-distribution fitting code BAGPIPES. We re-identify XRT191223 as a Galactic stellar flare. Conclusions. For several FXTs, there are multiple candidate host galaxies, which complicates deriving constraints on the origin of the FXT. Assuming association with (one of) those candidates, all are consistent with a (non-)relativistic white dwarf--intermediate mass black hole tidal disruption event (WD-IMBH TDE) and a binary neutron star (BNS) merger. Two are consistent with a supernova shock breakout and only EP240708a with cocoon emission from a long γ-ray burst. We also discuss the possibility that the host galaxies remain undetected in our observations. We conclude that FXTs detected by Chandra and XMM-Newton are likely to arise from a variety of origins, and we discuss the fact that part of this population differs from FXTs detected by the Einstein Probe, many of which appear consistent with a collapsar scenario.

MUSE imaging spectroscopy of the fullerene planetary nebula Tc 1

First Author: Walsh, J. R.
Instruments: MUSE
ProgramIDs: 105.20R7
BibCode: 2026A&A...713A.103W

Aims. The planetary nebula Tc 1 (PN G345.2--08.8), one of the rare group of Galactic PNe showing fullerene emission in the infrared, is spatially extended with high a surface brightness. Optical imaging spectroscopy enables the line and continuum structure and diagnostics to be examined, and permits a search for any correlations to the presence of fullerene dust. Methods. Tc 1 was observed with MUSE wide field mode with adaptive optics, wavelength range 4700--9300 Å, at three exposure levels to ensure unsaturated emission lines. Extinction, electron temperature (T_e), and density (N_e) diagnostic images are presented from collisionally excited and recombination line ratios. Results. The nebula has a high surface brightness core, with a diameter 12″, an elliptical ring of major axis 2.8″ around the central star and some low ionization knots, and an extended halo of 55″ in diameter; between the core and halo is an annulus with intermediate properties, including a higher T_e and a lower N_e than in the core. The spectrum of the central star was extracted and fitted by a 31 000 K model atmosphere and is of type O7.5I(f). The image of optical extinction from H Balmer line ratios is highly structured, and shows an annulus, which is adjacent to the core, of low extinction, with values lower than the line-of-sight interstellar extinction. Instrumental effects to account for this anomalously low extinction area were investigated and intrinsic effects from the scattering properties of the nebular dust; neither can entirely explain the low-extinction region and the most likely cause is a local non-standard dust reddening law. This low extinction region additionally shows an anomalously high He I 7281/6678 Å line ratio, possibly caused by a contaminating line, but none have been conclusively identified; its origin remains unresolved. Spectra over extended regions were also analysed and distinct enhancement of the continuum above the expected nebular continuum (as also seen in some other PNe observed with MUSE) was found. Conclusions. The annulus of low extinction occurs outside the region of strongest fullerene emission, in the zone where N_e declines and T_e rises. A change in dust properties linked to conditions in this transition region between the higher density core nebula and lower density halo is deduced.

A population view of transiting hot giant exoplanets: Tracing Fe and Ti chemistry with ESPRESSO and MAROON-X

First Author: Prinoth, Bibiana
Instruments: ESPRESSO
ProgramIDs: 106.20ZN
BibCode: 2026A&A...713A..84P

Hot and ultra-hot Jupiters offer a unique laboratory for studying atmospheric chemistry at the population level using ground-based high-resolution spectroscopy. Iron (Fe) and titanium (Ti) are key tracers of thermal and chemical structures, yet they exhibit markedly different observational trends across the population. We present a homogeneous re-analysis of high-resolution transmission spectra for ten hot and ultra-hot Jupiters observed with ESPRESSO on ESO's Very Large Telescope and MAROON-X on Gemini-North. We searched for neutral Fe and Ti absorption and performed injection--recovery tests using forward models spanning a range of Ti-depletion levels and temperature--pressure profiles. To enable direct comparison across planets observed with different instruments and signal-to-noise ratios, we introduced the relative cross-correlation metric, ∆_Ti-Fe. We detect Fe in seven planets and Ti in four planets at significances above 5σ. Across the population, ∆_Ti-Fe decreases sharply towards lower equilibrium temperatures. Under the assumption of equal Ti depletion across planets, isothermal models fail to reproduce this trend, instead requiring a temperature-dependent depletion of Ti that increases towards cooler planets, consistent with cold-trapping processes in cooler atmospheres. Models with inverted temperature--pressure profiles naturally reproduce the decline without invoking such temperature-dependent depletion. In these atmospheres, Ti is converted into TiO in deeper, cooler layers and subsequently removed from the gas phase through condensation into Ti-bearing species, leading to a strong suppression of the observable atomic Ti signal while Fe remains largely atomic. Nevertheless, even in these gradient models, an additional overall depletion of Ti relative to Fe is required to match the hottest planets. Our results demonstrate that the observable refractory chemistry is governed by the interplay of molecular partitioning, ionisation, condensation, and cold-trapping processes, as well as the vertical structure of ultra-hot Jupiter atmospheres. Although these results reveal clear population-level trends, additional observations will be necessary to distinguish between temperature-dependent cold-trapping and overall depletion scenarios. Expanding homogeneous high-resolution surveys to larger and more diverse samples, targeting both emission and transmission observations, will refine these constraints and provide critical insights into the chemistry of strongly irradiated giant planets.

An HI+radio continuum study of local cluster galaxies: Intercepting the early stages of environmental processing with MeerKAT

First Author: Ignesti, Alessandro
Instruments: MUSE
ProgramIDs: 196.B-0578
BibCode: 2026A&A...713A..90I

The evolution of galaxies in clusters is driven by their interaction with the environment. This deeply affects and alters the properties of the multiphase interstellar medium. We used MeerKAT observations to study the properties of the neutral and nonthermal interstellar medium, traced by the HI 21 cm line and by the radio continuum emission at 1.4 GHz, respectively, out to about twice the virial radius of three local (z ≃ 0.04) galaxy clusters, namely IIZW108, A4059, and A3558, with M₂₀₀ ≃ 2--9 × 10¹⁴ M_⊙. We assembled a sample of 61 galaxies, including the so-called jellyfish and unwinding galaxies, detected in HI and radio continuum, and derived their optical properties from IR-to-UV photometry using ancillary data. The cluster galaxies in our sample are ~2.7 times more star-forming on average than galaxies with the same stellar and HI mass in the field, indicating that the HI + radio-continuum selection has intercepted galaxies at the very early stages of their environmental processing when the external pressure has not yet removed the gas, but the resulting fast compression has enhanced the star formation and the radio continuum luminosity. Our study also reveals that galaxies in the initial stage can feature a radio luminosity excess because the old relativistic electrons permeate the interstellar medium. We show that unwinding galaxies are characterized by high stellar and HI masses, and we argue that their peculiar morphology might result from their high baryonic mass. Finally, via the stacking analysis of 677 optically selected cluster members, we quantitatively show that cluster galaxies are poorer in HI than in the field and that the deficiency steadily grows toward the cluster center, where the HI mass of galaxies is lower by a factor of about 3 than the HI mass of galaxies in the field.

pop-cosmos: redshifts and physical properties of KiDS-1000 galaxies

First Author: Halder, Anik
Instruments: OMEGACAM, VIRCAM
ProgramIDs: 179.A-2004, 177.A-3016, 177.A-3017, 177.A-3018
BibCode: 2026MNRAS.551g1590H

Principled Bayesian inference of galaxy properties has not previously been performed for wide-area weak-lensing surveys with millions of sources. We address this gap by applying the pop-cosmos generative model to perform spectral energy distribution (SED) fitting for 4 million KiDS (Kilo-Degree Survey)-1000 galaxies. Calibrated on deep COSMOS2020 photometric data, pop-cosmos specifies a physically motivated prior over the galaxy population up to

$z \simeq 6$

in stellar population synthesis (SPS) parameter space. Using the Speculator SPS emulator with GPU (graphics processing unit)-accelerated Markov Chain Monte Carlo sampling, we perform full posterior inference at 8.2 GPU seconds per galaxy, obtaining joint constraints on galaxy redshifts and physical properties. We validate photometric redshifts against

$\sim \!185\,\!000$

KiDS galaxies cross-matched to Dark Energy Spectroscopic Instrument Data Release 1 spectroscopic samples, achieving low bias (

$2\times 10^{-3}$

), scatter (

$\sigma _{\mathrm{MAD}}=0.03$

), and outlier fraction (3.2 per cent) for the Bright Galaxy Survey, with comparable performance (bias

$3\times 10^{-2}$

$\sigma _{\mathrm{MAD}}=0.05$

, 1.0 per cent outliers) for luminous red galaxies (LRGs). Within the LRG sample, we identify massive, dusty, star-forming contaminants at

$z \simeq 0.4$

satisfying standard colour selections for quenched populations. We infer trends in stellar mass, star formation, metallicity, and dust across five tomographic redshift bins consistent with established scaling relations. Using specific star formation rate constraints, we identify

$\sim$

7 per cent of KiDS-1000 galaxies as quenched, versus 37 per cent implied by conservative colour cuts. This enables the construction of weak-lensing samples defined by physical properties while mitigating intrinsic alignment systematics and preserving statistical power. Our analysis validates pop-cosmos out of sample, establishing it as a scalable approach for galaxy evolution and cosmological analyses with photometric surveys.

The SAMI galaxy survey: linking tidal features and orbit populations using Schwarzschild modelling

First Author: Rutherford, T. H.
Instruments: OMEGACAM, VIRCAM
ProgramIDs: 179.A-2004, 177.A-3018, 177.A-3016, 177.A-3017
BibCode: 2026MNRAS.551g1540R

The evolution of angular momentum in galaxies is shaped by a combination of internal secular processes and external mechanisms such as mergers. Orbit-superposition based dynamical modelling provides a powerful means of linking the intrinsic orbital structures of galaxies to their global properties and merger histories. We construct Schwarzschild orbit-superposition models of massive (

$\log _{10}\!\left(\rm {M}_*/\rm {M}_\odot \right)$

>10) SAMI galaxies using the DYNAMITE code, utilising deep Kilo-Degree Survey photometry to accurately reproduce each galaxy's luminosity distribution. We find that the fractions of hot, cold, warm, and counter-rotating orbits all show significant correlations with the spin parameter proxy

$\lambda _{R_{\rm {e}}}$

, with the strongest correlation arising from the combined hot plus counter-rotating fraction. When controlling for stellar mass and environment, we find that the fraction of hot and cold orbits show significant correlations with stellar age, whereas warm orbits do not. We further find that the lower values of

$\lambda _{R_{\rm {e}}}$

for young galaxies with shell merger features as compared to the full sample is driven by an excess of hot orbits and a deficit of cold orbits, with no dependence on warm orbits. We suggest that the kinematic transformation in this SAMI sample proceeds through stars transitioning directly from cold to hot orbits. As warm orbits are expected to arise from secular heating processes, these findings indicate that merger-driven heating is the dominant mechanism governing the redistribution of angular momentum and the reduction of rotational support in massive galaxies.

The ALMA survey to Resolve exoKuiper belt Substructures (ARKS): III. The vertical structure of debris disks

First Author: Zawadzki, B.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2012.1.00142.S, 2012.1.00198.S, 2015.1.01260.S, 2016.1.00104.S, 2016.1.00195.S, 2016.1.00907.S, 2017.1.00167.S, 2017.1.00825.S, 2018.1.01222.S, 2019.1.00189.S, 2022.1.00338.L
BibCode: 2026A&A...705A.197Z

Context. Debris disks ─ collisionally sustained belts of dust and sometimes gas around main sequence stars ─ are remnants of planet formation processes and are found in systems ≳10 Myr old. Millimeter-wavelength observations are particularly important, as the grains probed by these observations are not strongly affected by radiation pressure and stellar winds, allowing them to probe the dynamics of large bodies producing dust. The ALMA survey to Resolve exoKuiper belt Substructures (ARKS) is analyzing high-resolution observations of 24 debris disks to enable the characterization of debris disk substructures across a large sample for the first time. Aims. For the most highly inclined disks, it is possible to recover the vertical structure of the disk. We aim to model and analyze the most highly inclined systems in the ARKS sample in order to uniformly extract the vertical dust distributions for a sample of well-resolved debris disks. Methods. We employed both parametric and nonparametric methods to constrain the vertical dust distributions for the most highly inclined ARKS targets. Results. We find a broad range of aspect ratios, revealing a wide diversity in vertical structure, with a range of best-fit parametric values of 0.0026 ≤ h_HWHM ≤ 0.193 and a median best-fit value of h_HWHM = 0.021. The results obtained by nonparametric modeling are generally consistent with the parametric modeling results. We find that five of the 13 disks are consistent with having total disk masses less than that of Neptune (17 M_⊕), assuming stirring by internal processes (self-stirring and collisional and frictional damping). Furthermore, most systems show a significant preference for a Lorentzian vertical profile rather than a Gaussian.

Forecasting the Observable Rates of Gravitationally Lensed Supernovae for the PASSAGES Dusty Starbursts

First Author: Kamieneski, Patrick S.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2015.1.01518.S, 2016.1.00048.S, 2017.1.01214.S, 2019.1.01636.S
BibCode: 2026ApJ..1000..235K

More than 60 years have passed since the first formal suggestion to use strongly lensed supernovae (SNe) to measure the expansion rate of the Universe through time-delay cosmography. Yet, fewer than 10 such objects have ever been discovered. We consider the merits of a targeted strategy focused on lensed hyperluminous infrared galaxies, which are among the most rapidly star-forming galaxies known in the Universe. With star formation rates (SFRs) ∼200─6000 M_⊙ yr⁻¹, the ∼30 objects in the Planck All-Sky Survey to Analyze Gravitationally-lensed Extreme Starbursts are excellent candidates for a case study, in particular, and have already led to the discovery of the multiply imaged SN H0pe. Considering their lens model-corrected SFRs, we estimate their intrinsic SN rates to be an extraordinary 1.8─65 yr⁻¹ (core-collapse) and 0.2─6.4 yr⁻¹ (Type Ia). Moreover, these massive starbursts typically have star-forming companions which are unaccounted for in this tally. We demonstrate a strong correlation between Einstein radius and typical time delays, with cluster lenses often exceeding several months (and therefore most favorable for high-precision H₀ inferences). A multivisit monitoring campaign with a sensitive infrared telescope (namely, JWST) is necessary to mitigate dust attenuation. Nevertheless, a porous interstellar medium and clumpy star formation in these extreme galaxies might produce favorable conditions for detecting SNe as transient point sources. Targeted campaigns of known lensed galaxies to discover new lensed SNe can greatly complement wide-area cadenced surveys. Increasing the sample size helps to realize the potential of SN time-delay cosmography to elucidate the Hubble tension through a single-step measurement, independent of other H₀ techniques.

JOYS+: A JWST/MIRI survey of the evolution of H₂ winds and jets from low-mass protostars

First Author: Francis, L.
Instruments: ALMA_Band_6, ALMA_Band_7
ProgramIDs: 2013.1.00031.S, 2013.1.00726.S, 2017.1.00053.S, 2017.1.01078.S, 2017.1.01350.S, 2018.1.00701.S, 2019.1.00261.L, 2019.A.00034.S, 2021.1.00418.S, 2021.1.01578.S
BibCode: 2026A&A...711A.258F

Context. The base of protostellar outflows can display both wide-angle, low-velocity winds and high-velocity, collimated jets, the magnetocentrifugal launching of which enables accretion onto the protostar. In outflows from the youngest protostars, the majority of the ejected or entrained mass is likely molecular H₂ . How the H₂ outflow evolves as the central protostar grows and the envelope dissipates is important for understanding the nature of the launching mechanism and assembly of the nascent protostar. Aims. Using JWST MIRI/MRS observations with an unprecedented spatial resolution down to 0.3" towards 13 single and 20 multiple Class 0 and I protostars, we aim to investigate the H₂ wind and jet morphology, mass outflow rate, velocity and temperature structure, and the evolution of these properties with protostellar class. Methods. We constructed continuum-subtracted maps of the H₂ S(1) and S(7) line flux and velocity towards the outflows in our sample and ALMA sub-millimetre CO maps. Towards the base of each blueshifted outflow lobe (typically within 300 au), we extracted representative spectra and measured the outflow opening angles from the H₂ S(1) line emission. A rotation-diagram fitting of the H₂ lines was used to determine the column density and temperature, which was combined with measurements of the outflow width and H₂ line velocity to measure the mass-loss rates. Results. Low- J (J ≤ 4) transitions of H₂ largely trace extended wide-angle, low-velocity (0-20 km s⁻¹) winds within the contours of the low-velocity (<30 km s⁻¹) sub-millimetre CO emission, while high-J (J > 5) transitions are associated with shocks and knots. In Class 0 sources with a known high-velocity (>30 km s⁻¹) molecular CO or SiO jet, higher H₂ velocities are observed along the jet axis. The opening angle of the wind traced by the H₂ S(1) line broadens from ∼20° to ∼90° through the Class 0 to the Class I stage. The rotation diagrams in the blueshifted outflow lobes show a clear separation between a warm, ∼600 K and a hot, 1500-3000 K component, with no clear sign of evolution in the excitation temperature. The warm component contains two orders of magnitude more mass than the hot component, and the H₂ outflow mass-loss rate declines by two orders of magnitude from the Class 0 to the Class II stage. A correlation with the bolometric luminosity of the driving source is observed. A factor of 10─1000 mismatch between the warm H₂ and cold sub-millimetre CO outflow rate and momentum flux is also seen, which is consistent with the presence of cold and likely entrained (<150 K) molecular H₂ that cannot be detected with JWST/MIRI. Conclusions. The declining warm H₂ mass-loss rates and increasing opening angles from the Class 0 to I stages ─ and the absence of H₂ jets in the Class I sources ─ are consistent with the predictions of magnetohydrodynamical (MHD) disc wind models; however, the relatively constant temperatures of the warm and hot components with evolutionary stage may reflect the typical conditions in the outflow shocks rather than temperature stratification of the wind.

The most extreme high-z radio quasars in the eRASS:1 X-ray survey

First Author: Ighina, L.
Instruments: EFOSC2
ProgramIDs: 115.28BJ
BibCode: 2026MNRAS.551g1518I

We present the selection and identification of high-z radio quasars from a combination of X-ray (eROSITA All-Sky Survey), optical/NIR (DECam Local Volume Exploration), and radio (Rapid ASKAP Continuum Survey) surveys. After building a sample of 68 new high-z quasar candidates, we performed follow-up spectroscopic observations on 46 sources, confirming 39 to have redshifts

$z\gt 3.5$

. For the subset of radio quasars at

$z\gt 4$

, the 14 new sources identified here represent an increase of

${\sim} 65$

% in the known population of objects above the same flux limits in the same area. Using X-ray-to-optical relative intensity, we identified blazars in our sample, which we then used to compare the total number of

$z\gt 4$

, X-ray selected blazars to the predictions of a fractional IC/CMB model previously proposed in the literature. Overall we find a relatively good agreement, even considering the potential biases in the redshift distribution from the incompleteness of the spectroscopic follow-up and the blazar classification criteria. The sources presented in this work represent a sample well suited for investigating the evolution of the most extreme systems in the early Universe, including their relativistic jets and accretion properties.

Exploration of the inner region of the system HD 142527

First Author: Tran, T. M. H.
Instruments: SPHERE
ProgramIDs: 095.C-0298, 096.C-0241, 097.C-0865, 096.C-0248, 115.28BA
BibCode: 2026A&A...713A..25T

Context. HD 142527 is a well-studied intermediate-mass T Tauri star surrounded by a transitional disk with a large dust cavity, spiral structures, and an accreting low-mass companion. Despite extensive observations, the system's inner regions remain poorly understood, particularly regarding their influence on disk morphology and planet formation. Aims. This study aims to investigate the inner region of HD 142527 (separation <50 au) with high detection sensitivity thanks to dedicated post-processing methods to search for undetected components and explore their potential role affecting the disk's structure and evolution. Methods. We analyze high-contrast imaging data obtained with the SPHERE instrument at the Very Large Telescope (VLT). To enhance detection sensitivity, we applied the PACO and REXPACO algorithms, dedicated respectively to the detection of point-like sources and to the reconstruction of circumstellar disks with high reliability, while exploiting both angular and spectral variations. Results. We revisit the known companion HD 142527 B and update its photometry, astrometry, and accretion rate estimates. Furthermore, we identify a new candidate companion (CC) at an angular separation of ρ ~ 0.09″ (~14 au). Though it is shown as a point-like object, the possibility that CC is a disk feature remains. Otherwise, it could be a young gas-giant planet or a brown dwarf with a mass of 12--50 M_Jup. Additionally, we report the discovery of a tightly wound Hα spiral feature in the inner disk, reconstructed for the first time by high contrast imaging. The spiral implies varying accretion dynamically linked to the known companion B and possibly to CC, suggesting ongoing interactions that influence the disk's structure. Conclusions. Our findings provide new insights into the complex interactions within the HD 142527 system, highlighting the role of multiple companions in driving disk asymmetries and facilitating planet formation. Future high-resolution observations and dynamical modeling will be essential to fully understand the system's architecture and evolution.

VLT/MUSE Study of Close Active Galactic Nucleus Pairs and Host Galaxies in the Local Universe. I. Overview of the Ionized Gas

First Author: Xu, Xiaoyu
Instruments: MUSE
ProgramIDs: 0103.A-0637, 095.B-0482, 109.238W, 110.23WR, 0101.D-0748, 0100.B-0116
BibCode: 2026ApJS..286...30X

Studying active galactic nucleus (AGN) pairs and their host galaxies is essential for understanding the interplay between galaxy mergers and key internal processes such as supermassive black hole fueling and feedback. We crossmatch between the Big Multi-AGN Catalog and the public data archive of the Very Large Telescope (VLT)/MUSE, and obtain 12 AGN pair candidates in the local Universe (z ≲ 0.1) with a projected distance of r_p <= 20 kpc. Using archival VLT/MUSE data, we present a spatially resolved study of the ionized gas kinematics and ionization properties of these 12 AGN pair candidates. By decomposing the optical emission lines into two Gaussian components, we try to separate gas associated with disk rotation from noncircular motions. We further identify dominant ionization mechanisms using spatially resolved Baldwin--Phillips--Terlevich diagnostics. We find that both nuclei in four of the 12 systems are classified as a Seyfert or LINER. In addition, three nuclei are classified as star-forming or composite in the optical diagnostics, but are identified as AGNs at other wavelengths. Kinematically, regularly rotating ionized gas disks are detected in 16 of 24 nuclei. Prominent tidal features traced by ionized gas are also detected in nine systems. Ionized gas outflows are widespread and are detected in 18 nuclei. Finally, for three nuclei (Mrk 739A, NGC 7592B, and J1544+0446A), we find evidence for fading AGN activity over the past several tens of thousands of years, based on optical emission-line ratios and an assumed AGN photoionization model.

ALMA High-J CO Spectroscopy of High-redshift Galaxies. II. 0 .″ 03 Resolution CO Kinematics Reveal S

First Author: Tadaki, Ken-ichi
Instruments: ALMA_Band_5, ALMA_Band_7
ProgramIDs: 2021.1.00168.S, 2022.1.00353.S, 2024.1.01175.S
BibCode: 2026ApJ..1006..117T

We present ultrahigh-resolution ( 0.″03≍230 pc) Atacama Large Millimeter/submillimeter Array (ALMA) observations of the hyperluminous dust-obscured galaxy W2305−0039 at z = 3.111, targeting the CO J = 7─6 and J = 11─10 lines. The CO (11─10) emission is extremely compact and exhibits anomalously high excitation relative to CO (7─6) within the central ≲500 pc. X-ray-dominated region models successfully reproduce this excitation, providing strong evidence for intense X-ray irradiation by a deeply obscured active galactic nucleus (AGN), while photodissociation region models fail to match the observed ratio. Forward modeling of the nuclear CO(11─10) position─velocity diagram yields a dynamical black hole mass of log(MBH/M⊙)=8.3−0.6+0.7 and an intrinsic gas velocity dispersion of σgas=277−14+16 km s⁻¹. Combined with the AGN luminosity from infrared spectral energy distribution decomposition, these measurements imply a highly super-Eddington accretion state with λ_Edd ≳ 4. Our results provide dynamical evidence that the most rapid phases of black hole growth can occur within a compact, heavily obscured nuclear region. Extending ALMA beyond its current 16 km maximum baselines will be essential for pushing such dynamical measurements to tens-of-parsec scales and resolving the black hole sphere of influence in massive galaxies at z ≳ 6.

Three new exoplanet systems from the Dispersed Matter Planet Project

First Author: Barnes, J. R.
Instruments: ESPRESSO, HARPS
ProgramIDs: 098.C-0269, 0100.C-0836, 114.27LM, 099.C-0798, 095.C-0799, 097.C-0390, 110.248C
BibCode: 2026MNRAS.551g1486B

We present a radial velocity analysis of three bright, low-activity stars identified by the Dispersed Matter Planet Project (DMPP). We use a Bayesian framework to compare purely Keplerian models with models incorporating stellar activity via a quasi-periodic Gaussian Process (GP). DMPP-7 (HD 118006) is a slightly evolved star that harbours a single 0.72 Saturn-mass giant (

$m_\rm {p}\, \sin \, i$

$= 69$

$_{\oplus }$

) with an orbital period of

$P=4.93$

d. A longer 21 -- 22 d period cannot be conclusively confirmed as a stellar rotation signature rather than a purely Keplerian signal. For HD 67200, which exhibits Ca II H&K variability, a model with only a GP is strongly favoured over a purely dynamical model. The GP model shows moderate evidence for a single Keplerian with

$P=2.67$

d. For HD 2134, a 21 -- 32 d rotation period signal is associated with tentative Full Width at Half Maximum variability. A model with a GP is not conclusively favoured, but all models considered show moderate evidence for an additional single Keplerian with

$P=2.78$

d. Despite our target selection favouring near edge-on orbital geometries, we find no evidence for transits in Transiting Exoplanet Survey Satellite photometry. DMPP-7 b lies at the transition between the high-radius population and the Neptunian ridge and savannah regions. Further observations are required to establish whether the coherent short-period HD 67200 and HD 2134 signals are stellar or dynamical in origin. If planetary, the signals correspond to minimum masses of

$m_\rm {p}\, \sin \, i$

$= 2.07$

$_{\oplus }$

and

$m_\rm {p}\, \sin \, i$

$= 2.86$

$_{\oplus }$

The Exceptional 2017 γ-Ray Flare of the Radio Galaxy NGC 1275: VERITAS and Multiwavelength Observations

First Author: Acharyya, A.
Instruments: ALMA_Band_3, ALMA_Band_5, ALMA_Band_6, ALMA_Band_7, ALMA_Band_9
ProgramIDs: 2012.1.00394.S, 2016.1.01305.S, 2017.1.01257.S, 2018.1.01438.S
BibCode: 2026ApJ..1006...12A

The radio galaxy NGC 1275 is the brightest cluster galaxy in the Perseus Cluster. It is well studied across all wave bands, including very high-energy (VHE; E ≥ 100 GeV) γ-rays, and with radio observations over the last 20 yr tracking an unusual radio component, "C3." NGC 1275 was observed in an exceptional VHE-flaring state between 2016 December 31 and 2017 January 3. The flare peak reached ∼1.5 Crab units as measured by the MAGIC observatory. We report on the observations of NGC 1275 conducted by VERITAS and multiwavelength data collected during this flaring state and, for context, data taken between 2009 and 2017 inclusively. VERITAS detected the declining state of the flare on 2017 January 2 (MJD 57755) and 3 (MJD 57756) at an average flux state of 0.5 Crab units. VERITAS spectra show an overall long-term trend of harder when brighter. During the flare, the γ-ray spectrum obtained from the combined Fermi-LAT, MAGIC, and VERITAS observations changes from a power law with an exponential cutoff on January 1 to a log-parabola on January 2. To study the evolution of the flare in more detail, multiband spectral energy distributions (SEDs) were constructed for the nights of 2017 January 1 and 2 corresponding to the shift from the peak to the decline of the flare. A blob-in-jet modeling of the SEDs results in support for a two-component model with a θ = 10^∘ jet angle to the line of sight and the γ-ray emission zone located in the vicinity of the C3 radio component.

A closer look at the WISPIT 2 host star: Evidence of a spectroscopic binary

First Author: Burgy, C. J.
Instruments: XSHOOTER
ProgramIDs: 116.2ASZ
BibCode: 2026A&A...713L...1B

Context. While hundreds of protoplanetary discs have been studied in great detail, the detection of protoplanets that are still embedded in their native discs remains rare. WISPIT 2 is only the second laboratory allowing us to directly study planet formation while in progress. The recently discovered system hosts two giant protoplanets in a multi-ringed disc. Aims. We characterise the WISPIT 2 host star spectroscopically to determine its stellar properties, accretion rate, and inner disc diagnostics to provide a more complete picture of the system. Methods. We present optical and near-infrared spectroscopic observations obtained with the ESO VLT/X-shooter and 2.2 m/FEROS instruments. We modelled the stellar spectrum to determine the spectral type and effective temperature, analysed the emission lines to estimate the accretion rate, and searched for evidence of a close stellar companion using radial velocity measurements. Results. Our observations reveal that WISPIT 2 is a spectroscopic binary. The binary has a period of (4.8 ± 0.1) days, which corresponds to a semi-major axis of 0.072 au or 15.54 R_⊙, assuming co-planarity with the disc and a circular orbit. The binary system consists of a ~0.97 M_⊙ primary of spectral type K3 (T_eff ~ 4700 K) and a ~0.33 M_⊙ secondary (mass ratio ~0.34). We detect weak Hα emission below the typical chromospheric level, indicating little to no ongoing accretion onto the young stars, consistent with an accretion rate of ≲2 × 10^-11 M_⊙ yr^-1. Conclusions. This discovery makes the WISPIT 2 disc the first circumbinary system with directly imaged protoplanets and establishes this system as a unique benchmark for studying planet formation and disc evolution around binary stars.

Discovery of a low-surface-brightness galaxy in the Zone of Avoidance using VVVX Deepstack imaging

First Author: Nilo-Castellon, J. L.
Instruments: VIRCAM
ProgramIDs: 179.B-2002, 198.B-2004
BibCode: 2026A&A...713L...3N

We report the discovery of VVVX J080705.96-273823.6, the first low-surface-brightness galaxy candidate identified in the Zone of Avoidance by the VISTA Variables in the Vía Láctea eXtended Survey (VVVX). The source was detected serendipitously during a visual inspection of the new Deepstack images, a set of reconstructed mosaics generated through an updated reprocessing. The associated stacking procedure that significantly improves both the depth and spatial uniformity of the original survey images. First-order morpho-photometric parameters were obtained using SExtractor in combination with PSF models derived with PSFEx, applied to star-subtracted images to minimize foreground contamination. The final structural properties of the galaxy were derived from PSF-convolved modelling of azimuthally averaged surface-brightness profiles in the J, H, and K_s bands using exponential, Sérsic, and composite models. The galaxy candidate is clearly detected in the three available near-infrared bands. The azimuthally averaged profiles are consistently described by a disk-dominated (exponential) model in all three bands, with exponential scale lengths in the range h ~ 32--36″ and extinction-corrected central surface brightness values spanning μ₀ ≃ 19.82--22.35 mag arcsec^-2. The J band gives the best-constrained profile; H and K_s show the same behaviour with larger uncertainties. The projected proximity to the galaxies ESO 494-25 and ESO 494-26 raises the possibility of a physical association. Both ESO galaxies have radial velocities consistent with distances of ~11--12 Mpc. If VVVX J080705.96-273823.6 were located at the same distance, its characteristic exponential scale length of h ≃ 34″ would correspond to ~1.8--2.0 kpc, consistent with the range of scale lengths observed in nearby LSB disk galaxies. However, in the absence of a spectroscopic redshift, this association remains tentative. This discovery demonstrates that the new VVVX Deepstack products can reveal faint diffuse galaxies at low Galactic latitudes, opening a path toward a more complete census of the obscured nearby Universe.

3D rotation of the open cluster NGC 2516

First Author: Wright, Nicholas J.
Instruments: FLAMES, GIRAFFE, UVES
ProgramIDs: 188.B-3002
BibCode: 2026MNRAS.551g1576W

We have combined Gaia astrometry with Gaia-ESO Survey radial velocities to measure the 3D rotation of the open cluster NGC 2516. We compiled a sample of 376 members with astrometry and spectroscopy and use these to determine a distance to the cluster of

$406.4 \pm 0.8$

pc, which we then use to infer the 3D positions and velocities of all stars in the cluster using a Bayesian model. We identify the axis of maximum cluster rotation and measure a median rotational velocity of

$0.11 \pm 0.02$

km s

$^{-1}$

. We find the axis of maximum cluster rotation to be

$52^\circ \pm 22^\circ$

to the plane of our Galaxy. We compare this rotation rate to measurements of cluster rotation in other open clusters and find that it is inconsistent with the expected dependences on cluster age and mass.

Light curve and spectral properties of Type II supernovae from the ATLAS survey

First Author: Ertini, K.
Instruments: EFOSC2
ProgramIDs: 1103.D-0328, 106.216C, 108.220C
BibCode: 2026A&A...713A..29E

Context. Type II supernovae (SNe) are the most common terminal stellar explosions in the Universe. With SNe now being detected within days after first light, there is growing evidence that most Type II SNe (SNe II) show signs of interaction with a dense, confined circumstellar material (CSM) in the first few days after first light. Aims. We aim to bridge the gap between single SN studies showing early-time interaction in their spectra and statistical studies of early-time SN light curves, which imply the existence of CSM. Methods. We present a sample of 68 Type II SNe with both early photometric data obtained by the ATLAS survey and spectroscopic data obtained by the ePESSTO+ collaboration. A subset of the sample is classified based on the presence or absence of narrow spectral features with electron-scattered broadened wings in the early spectra, indicative of interaction with the CSM. We characterised the photometric and spectroscopic properties of the sample by measuring rise times to maximum light, peak magnitudes, decline rates, and line velocities. Additionally, we measured the ratio of absorption to emission (a/e) of the Hα P-Cygni profile. Results. Our analysis reveals that SNe II showing early spectroscopic signs of interaction with the CSM decline faster and are brighter than those without. However no difference was found in rise times between the two groups. A clear separation can be observed in the a/e ratio, namely, SNe with signs of interaction exhibit lower a/e ratios at all epochs compared to those without. Our results highlight that understanding SN II ejecta-CSM interaction requires large uniform samples of photometric and spectroscopic data, such as the one presented in this work.

SN 2019cqc: A Hydrogen-rich Superluminous Supernova Showing Electron-scattering Signatures

First Author: Hebbar, Dinesh
Instruments: EFOSC2
ProgramIDs: 1103.D-0328, 106.216C
BibCode: 2026ApJ..1008..135H

Hydrogen-rich superluminous supernovae without narrow emission lines (SLSNe-II) are rare transients whose powering mechanisms remain debated, particularly the role of circumstellar medium (CSM) interaction. We present photometric and spectroscopic observations of SN 2019cqc to investigate its power source and progenitor mass loss. We model the lightcurve using MOSFiT with the csm and csmni models to constrain the explosion and CSM parameters. SN 2019cqc peaked at M_g = -20.21 ± 0.07 and emitted ~1.7 × 10⁵⁰ erg of energy in the form of radiation. Photometric and spectroscopic modeling indicates that CSM interaction dominates in both scenarios, with best-fit CSM and ejecta masses of ~4.5 M_⊙and ~32 M_⊙, respectively. The inferred CSM properties imply an extreme eruptive mass loss at a rate of ~0.2--0.3 M_⊙, yr^-1 in the years preceding the core collapse, consistent with a variable progenitor of luminous blue variable progenitor. We observe a persistent blueshifted asymmetry in the Hα emission line. At early times (≲+110 days), this is attributed to electron scattering with the bulk velocity of ejecta, while the profile at late epochs (≳ +402 days onward) suggests the subsequent formation of dust in the ejecta. Additionally, we identify a distinct, short-lived feature at ~4600 Å, likely a blend of ionized C III/N III lines powered by the interaction of the SN-shock with the extended atmosphere.

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