Back in July I wrote about my involvement in a new Zooniverse citizen science project, the then unnamed Project IX. In the last few months, Project IX became the Milky Way Project, and today yesterday it went live! A massive congratulations to Rob and the team who did a fabulous job in getting this all together.
In the Milky Way Project, we’re showing you colour images from our galaxy, the Milky Way, which were created from three wavelength channels from instruments on board the Spitzer Space Telescope. Spitzer observes the Universe in the infrared, and is therefore sensitive to objects that are colder than those that emit visible light. This includes the dense dusty clouds, concentrated in the disk of our galaxy, in which new stars are being formed. Although Spitzer is small in size, it has opened up a new window on our own and more distant galaxies in the infrared. The hundreds of thousands of images in its science archive are rich hunting grounds – particularly for those interested in star formation studies.
The surveys that the Milky Way Project images were taken from, the GLIMPSE and MIPSGAL projects, have mapped the plane of the Galaxy in unprecedented detail. The images are littered with clouds of gas and dust, lit up by bright young stars, clusters, or supernova remnants. Sinister-looking wispy infrared dark clouds (IRDCs) mark the suspected birth locations of the most massive stars. The richness of these data is immense, and the Milky Way Project volunteers are asked to help classify as many features as possible.
In this first stage of the project, the focus is on bubbles. In 2006, Ed Churchwell of the University of Wisconsin at Madison and collaborators published a paper studying more than 300 bubbles they had visually identified from GLIMPSE images. They looked at their characteristic shapes and sizes and how they are distributed in the galaxy. The hypothesis is that these bubbles are showing gas that was swept up by the intense radiation from young hot stars at their centres. Some of the bubbles do show a central star or cluster, consistent with this theory.
In their paper, the authors talk about the difficulties of finding these objects by visual inspection of images with a small group of people: some authors gave preference to smaller or larger bubbles, and assessments of bubble size and thickness were quite discrepant between different observers. In short, this is a perfect task for a large number of people to increase the confidence in bubble parameters.
By getting volunteers to pore over these fantastic images, we can assemble a much larger database of these bubbles and learn about their nature and formation process, and ultimately about the early evolution about young, hot stars.
Go take a look and have a play – every classification helps. I’ve spent quite some time in recent weeks and months playing with the interface, and my advice is not to rush these images. With Galaxy Zoo, I found I had to follow my gut feeling on the shapes of galaxies as soon as I saw them. If I looked at them for too long, I could never convince myself either way. But I find these bubble structures sometimes take a while to appear, particularly in busy images with lots of filaments, clouds, colours. Some bubbles are tiny, others don’t even fit into the frame; some are perfectly round, others are broken into arcs or very oval in shape. But they all matter.
The interface lets you pick out other interesting objects, and do check out the tutorial for some examples of these. I also found that playing with the brightness of my screen helped find more objects, as brightening or dimming the image can bring out new features you didn’t initially see.
Finally, something that maybe needs saying more often: thanks to all the Zooniverse volunteers! Your work really does matter, and we’re excited about the new things we’ll learn from your classifications.
Churchwell, E., Povich, M., Allen, D., Taylor, M., Meade, M., Babler, B., Indebetouw, R., Watson, C., Whitney, B., Wolfire, M., Bania, T., Benjamin, R., Clemens, D., Cohen, M., Cyganowski, C., Jackson, J., Kobulnicky, H., Mathis, J., Mercer, E., Stolovy, S., Uzpen, B., Watson, D., & Wolff, M. (2006). The Bubbling Galactic Disk The Astrophysical Journal, 649 (2), 759-778 DOI: 10.1086/507015