Spitzer's view of the central regions of our Galaxy (NASA/Milky Way Project)

Since its launch little more than over a year ago, Milky Way Project, the citizen science initiative to identify bubbles in the interstellar medium of our Galaxy, has gathered an amazing amount of classifications: over half a million bubbles drawn by around 35,000 users. Before Christmas we reached a major milestone when we submitted our first scientific paper for the project to Monthly Notices of the Royal Astronomical Society (MNRAS).

Following some nice iterations (never said I didn’t like peer review….) with the referee for the paper, and coverage by the BBC at the AAS conference in Austin, TX, in January, we posted the paper to Arxiv a couple of weeks ago. From here it’s available to anyone to download and read. The paper was formally accepted today (yay!) but we haven’t uploaded the final revision to the Arxiv yet – keep an eye out for it in the replacements section if you’re interested, we did improve it significantly with the input of the referee.

As the project was only made possible by NASA publicly sharing the data from the Spitzer Space Telescope, we have of course made our first data catalogues publicly available as well on a dedicated site and on FigShare.

What’s in the paper?

As is customary, we give a description of the science questions we’re addressing in the opening section, with references to previous work. What’s the nature of these bubble-shaped structures we see littered around the Galaxy, and why are we interested in the HII regions they enclose? We describe the typical appearance of bubbles in our data colour scheme: bright green rims with filaments or secondary bubbles, often with toroidal red emission in their interior, and what these properties might physically signify.

The second introductory section describes our approach, data selection, the Milky Way Project interface and the design of the drawing tools we included.  If you’ve classified bubbles, this will be familiar stuff. Then we go on to the data processing and the science.

One of the biggest lessons I’ve learnt from MWP is that the citizen science approach taken by the Zooniverse projects, while it provides a clever solution to some specific problems, doesn’t lead to easy answers. What really happens is that a visual task, which is hard to perform with a computer, is transformed into a data task, which computers are good at. Basically, images are converted into numbers via human brains. Lots of brains, and lots of numbers. How to make sense of all that?

Computers are really only as clever as we make them, so we had to come up with an intelligent way of processing the classifications into a reliable catalogue of bubble objects. In section 3 of the paper we show in detail how we achieved that. We wrote an algorithm that goes through the entire set of images, and finds clusters of classifications. When a cluster of 5 or more drawings is found, their coordinates are added to a separate table. The algorithm examines progressively smaller areas of the sky, until no bubbles drawings are left to be found, and then it moves on to the next section.

Finding clusters of objects in images of the sky is a very common task in astrophysics – finding stellar clusters or clusters of galaxies in large survey sets for example – and lots algorithms exist for doing this. Experimenting with more sophisticated cluster-finding methods is something we’d like to do for a following paper. But no method is perfect, there will always be false positive detections or clusters missed, and for our first data release we were satisfied with the results of our simple approach.

This process leaves us with clusters of bubble drawings that we had to process into one bubble, with a position and size. But is each drawing of the same quality? Do we just average the numbers, or do we try to assess how good or bad a drawing is in relation to the others? how do we deal with outliers? Just like we’d have to do with an instrument, we have to calibrate the classifications.

The solution we used is to discard every user’s first ten classifications, even our own, and from there on in we assigned points to users depending on how many bubbles they’d drawn using the full toolset. Essentially we assume that users who frequently adjust the shapes and sizes of the bubble drawings are precise and careful in their approach, and the more they do this the higher we weight their work.

These strategies weren’t picked out of thin air: we benefited a lot from the experience with previous Zooniverse projects, like Galaxy Zoo, and we tested any new methods quite extensively before accepting it into our “baseline” processing algorithm. And as I pointed out in previous posts on the MWP blog, these strategies are no reflection on the “right-ness” or “wrong-ness” of the drawings, we simply try to benchmark them against one another. After the first 10 drawings every one does count and contribute to the final catalogue.

What’s in the catalogues?

The entry page to the data catalogue for now contains just the bubble catalogues. The link prompts you to download a zip file containing two separate csv files (comma-separated variable files), which you can read either with a simple text editor, load into a spreadsheet in Excel or Numbers, or a more sophisticated table application like TopCat (if you’re nifty with code you can obviously write your own scripts too).

The first catalogue contains the “large bubbles”, or the bubbles that were drawn with the full toolset on the webpage, that lets the user adjust sizes and shapes. The “small bubbles” catalogue contains those objects that were too small to draw with the tools, which were simply marked with a box. The files contain 3744 large and 1362 small bubbles; 5106 objects in total.

If you want to explore the data visually, Rob created a Data Explorer page you can access from the Data webpage, which is really neat.

What will the catalogues be used for?

The original papers by Ed Churchwell and his collaborators from 2006 and 2007, which presented the first bubble  catalogues containing just a few hundred objects, have racked up almost 150 citations between them in 6 years, so there’s certainly interest in the community for this type of object.

Other scientists have particularly used the data to compare the infrared properties of these expanding HII regions with data from other wavelengths – radio, submillimetre, far-infrared or optical – to get more comprehensive pictures of specific star forming regions (e.g. Bik et al 2009, Marco & Neguerela 2011) . The data have also frequently been referenced in theoretical work simulating the expansion of these shells into the dense interstellar medium (e.g. Dale et al 2009), how newly born massive stars affect their surroundings and so on .

Authors have studied the rims of bubbles to locate potential areas of star formation that were triggered by the expansion of the shell into the surrounding dense cloud material (e.g. Watson et al 2010, Thompson et al 2012, Rodon et al 2010). This is a very active field of research, as this mechanism can potentially explain how star formation can propagate through a galaxy. But finding the observational evidence is tricky.

So we know there’s an interest in bubbles in general, and in particular the large sample size our citizen science approach has given us will make it particularly attractive for statistical follow-up studies.

And finally….

Rob Simpson, who leads the project at the University of Oxford and who really bore the brunt of the work for the project setup and this paper, will be on the BBC’s The Sky at Night in early March. He’ll talk about the Zooniverse projects he’s been working on and I expect he’ll talk about Milky Way Project as well. I hope the programme comes to BBC iPlayer soon so I can enjoy it here in these foreign climes.

Reference

R. J. Simpson, M. S. Povich, S. Kendrew, C. J. Lintott, E. Bressert, K. Arvidsson, C. Cyganowski, S. Maddison, K. Schawinski, R. Sherman, A. M. Smith, & G. Wolf-Chase (2012). The Milky Way Project First Data Release: A Bubblier Galactic Disk MNRAS arXiv: 1201.6357v1
 

[Cross-posted from ResearchBlogging News]

On All That Matters, Joerg Heber writes about a neat variation on the familiar coaxial cable: the coaxial laser. A new member of the family of light emitters with a host of potential applications.

How would the Earth have evolved without its Moon? Greg Fish describes how life on Earth might have been dramatically different without our little companion - though possibly still present.

Thinking about the origins of life has never been more topical, now that we’re learning about the strange new worlds all around us. On the Genealogy of Religion blog, this interesting post talks about pioneering experiments in this area.

That’s it for this week. I’ll be back next Monday with more selections.

In the mean time, I wanted to share the announcement of this interesting instrumentation school taking place in Toronto this summer. Since a few years, the University of Toronto hosts the Dunlap Institute, which is specialised in astronomical instrumentation. It’s really great to see such centres of excellence being set up – after all, very little science without good instruments. This course looks excellent for students who would like to get involved in instrumentation.

[Cross-posted from ResearchBlogging News.]

Today’s selections all seem to show us a glimpse of awesome new technology in a bright if distant future.

The shrinking magnetic storage devices story made some waves in the media, but not all stories got the science right. On All that matters Joerg Heber sets the record straight, and describes really nicely why this work should excite us.

Char’s Basal Science post on glow in the dark materials reminded me of the disappointingly faint glowing stars I once decorated my bedroom with. The science behind the phenomenon is pretty cool though, and the newly developed long-duration phosphorescent material he describes holds promise for exciting future applications.

How much water could we save if we could clean our clothes by just leaving them out in the sun for a few hours? Also on Basal Science, Cath talks about new developments in the quest for self-cleaning fabrics.

Have a great week, and I’ll be back next Monday with more picks.

In recent years the E-ELT project, Europe’s flagship next-generation optical observatory, seems to have gone from strength to strength: in 2010-2011, ESO Council officially gave the green light to the baseline technical design of the telescope (with the primary mirror slightly reduced in size), several member countries pledged their support for the project, others announced substantial investments into the development of hardware and instrumentation, and crucially, membership fees from giant new member state Brazil looked set to provide a major boost to the project’s financial coffers.

But apparently the E-ELT has hit a snag. This article in Brazilian publication Veja talks about Brazil’s failure to ratify the accession to ESO and support for the E-ELT project because of financial difficulties in 2011. Although an agreement was signed between ESO and the then science minister of Brazil in December 2010, Brazil’s parliament has yet to give its approval. Since then, Brazil’s been through general elections, and the new science minister hasn’t been forthcoming in continuing this approval process.

As Brazil’s contribution to ESO is crucial for the project to go ahead as long as no other new members join, the European members’ governments cannot now commit until Brazil formally comes into the club, and the project has been put on hold. ESO Director-General Tim De Zeeuw made some strong statements to the press about Brazil dragging its feet on the ratification, saying that the current accession conditions cannot be guaranteed beyond mid-2012, and new countries are lines up to join ESO if Brazil drop out. The article lists Australia, Israel, Russia, Poland and Estonia as potential new members.

An awkward point is that following the initial agreement in late 2010, Brazilian astronomers were already given full access to ESO telescope time. If Brazil now fail to ratify their accession, that privilege may be revoked again. That would be a big shame for their observers, who may have already planned multi-semester projects on ESO’s telescopes.

I can imagine that ESO really (really!) don’t want to start having negotiations with new member states at this point, as that’s likely to set the project back even further. Meanwhile the instrumentation community in Europe is working hard to keep the instrumentation projects for the new telescope alive, funded and staffed before getting the go ahead for the next phase of development.  I hope it happens soon!

Thanks to friendly Portuguese colleague Elisabete da Cunha for translating the article.

Image: Swinburne Astronomy Productions/ESO

This past week the UK collectively discovered its love for stargazing with the help of the BBC and a whole lot of keen astronomers. Professionals and amateurs took part in Stargazing events all over the country, and even more watched along on TV. 3.8 million of them, apparently, which is amazing.

Lots of my on- and offline friends and colleagues were on the air, and I was really disappointed I couldn’t watch, as I’m abroad and no TV. Some years ago I spent a summer at the BBC working on a similar programme (yes, I even met Brian Cox) and I have a lot of fun memories from that time. But anyway, I hope lots of you enjoyed watching or taking part, whether you’re an old hand in the business or an astro-newbie.

Planethunters, Milky Way Project‘s cousin in the Zooniverse family, got some special attention, as new volunteers signed up in droves to carry out almost 1.1 million new classifications in 48 hours. As a result, the Planethunters team were able to announce the discovery of a potential new exoplanet by a Stargazing viewer.

This great little video’s been doing the rounds on the interwebs, created on the back of BBC Stargazing, showing how and why we simulate galaxies. It was created by Oxford astronomer Andrew Pontzen, who featured on the programme.

Maybe one day I’ll work at one of these great institutes and hang out in its gorgeous library.

[Cross-posted from ResearchBlogging News.]

In astronomy the talk is all of exoplanets at the moment, but it’s good to remember our own Solar System is just as weird and wonderful as these new foreign worlds. On Basic Space, Kelly Oakes talks about new weather models on Titan. Cloudy with a chance of methane!

It’s a beautiful game that transcends politics, class and conflict – or so we like to think. Scientists in Japan, however, see football as “a competitive relationship between two cooperative networks“. So there. On Science Left Untitled, Charles describes this interesting new study of the network dynamics of football.

Wait, what was I saying about exoplanets again? The latest story to emerge last week was that our Galaxy may well contain more planets than stars, which is quite an amazing claim. Greg Fish dissects the paper and its methods on weird things.

That’s all for the week! I’ll be back next Monday with more physical sciences picks.

It’s been a busy week for the Milky Way Project team, on both sides of the Atlantic Ocean. Several of us are at the AAS conference in Austin, TX, and we’ve spent much time talking about the next steps for our project, and follow-up studies to get started with using our first data release.

Back at Zoo HQ in Oxford, Rob Simpson finalised the revisions to the paper and resubmitted it to the journal (MNRAS), where it will hopefully be accepted very shortly.

We took advantage of the big media presence here in Texas to chat to Jason Palmer, Science Reporter for the BBC. This has resulted in a really nice piece on BBC today describing the project and its first results. Science teamer Eli Bressert provided some snappy quotes too.

I’ll write a little more about the science once the paper is posted to astro-ph. For now I can say that Milky Way Project has been brilliant to work on from the very start, and I’m really thankful to my great collaborators and of course to all the volunteers who donated their time and eyes for our study.