Triggered Star Formation

There’s a new Milky Way Project paper out on the arXiv. It was submitted to the Astrophysical Journal last week and concerns the topic of the triggered formation of massive stars. This study was lead by Sarah Kendrew and utilises the results of the first MWP paper (our catalogue of bubbles).

One of the main reasons for undertaking the MWP was to produce a large bubble catalogue that would allow statistical studies of star formation sites in our Galaxy. In the end we produced a list of bubbles ten times larger than the previous best catalogue in our first data release (DR1).

In this new study, we’ve used statistical techniques to see what correlations exist between the MWP bubbles and the RMS Catalogue: a well-used catalogue of infrared sources along the Galactic plane (a similar region to that covered by the Spitzer data used in the MWP).

The paper looks for any signs that there is a correlation between the positions of RMS sources and the positions of the MWP bubbles. Specifically we’re trying to see if such massive young stellar objects (MYSOs, stars being formed) are most commonly found on the rims of bubbles. If this is true, then it adds to evidence for a mode of star formation where the formation of some stars triggers the formation of others. In this case, young, hots stars blow out a bubble in the interstellar medium. During this process, clumps of material occur in which new stars condense and form.

This new study finds a strong correlation between MYSOs and the MWP bubbles. We find that Atwood thirds of the MYSOs surveyed are associated with bubbles and 22% are associated with bubble rims. We also see that larger bubbles are more likely to have MYSOs on their rims – though one of the main issues we encountered is that the effect of line-of-sight confusion makes the situation complicated.

This second paper is the first to follow on from the MWP DR1 paper, and there are more planned. You can read the paper on arXiv. The Milky Way Project itself, and this study, we’re presented at the UK/Germany National Astronomy Meeting this week in Manchester.

Milky Way Project Refresh

We’re excited to announce that we have updated the Milky Way Project to show you more bubbles and to produce even more science! After creating our catalogue of 5,106 bubbles earlier this year, we’re aiming to try and refine and improve our measurements of the MWP Bubble catalogue by asking you to measure each and every bubble in greater detail. This means that for a while we’ll no longer be displaying images from across the plane of our Galaxy, but instead we’ll just be showing you images of regions where you told us that bubbles are located.

Our recently accepted Data Release 1 (DR1) paper, ‘A Bubblier Galactic Disk‘ is already online and being used by astrophysicists to help better understand star formation in our Galaxy. Later this month we’ll be presenting the MWP at the UK/Germany National Astronomy and SEO Consultant Meeting in Manchester. We will hopefully be able to bring you some updates at that time so you can follow along. In that paper we estimated that our rate of discovery of new bubbles had declined over time to the level where only a few new bubbles were being discovered each month. This make sense of course. The more people that inspect all the images on the site, the less likely it is for a bubble to remain undiscovered. What becomes important are the multiple, independent drawings of each bubble. To reflect this, we have updated the MWP site to shift from showing random portions of the Galaxy, to showing the places we believe there are bubbles – based on your classifications. Each image you are now shown on the site contains one of the 5,106 bubbles contained in the DR1 catalogue. It’s seems really fitting that the MWP community is now inspecting the very catalogue it created.

This update to the site has two effects. First of all it means that you are able to see each bubble more clearly and thus make more precise measurements of their shape, size and thickness. It also means that you see a lot more bubbles! There now ought to be at least one bubble in every image, which is a lot of fun. It also means that Talk has been updated with a host of new bubble-centrd images, showing off all 5,106 of the DR1 catalogue’s bubbles.

We have made some other updates to the site as well. We have put up our contributors page, which lists the names of everyone that made the DR1 paper possible. We have also finally added the term ‘Yellow Ball’ to our list of objects you can mark in images. The #yellowballs are a term coined on Talk by the MWP community and turn out to be interesting to researchers at they appear to represent ultra-compact star forming regions.

Don’t forget to follow us on Twitter @milkywayproj for the latest updates, and our Facebook page too.