I’m going to do some bragging for Ann and Sabrina here. They both have had papers recently accepted to astronomical journals for publication (and Sabrina’s has been published online already because I’m a little slow), which means they posted these papers to the astro-ph arXiv. The arXiv is an online preprint server where scientists post their papers before publication so that the community can see exciting results as soon as possible.
Ann‘s paper is a presentation of a catalog of sources from the ALFALFA survey. Ann took a strip of the survey area and found all the sources – both galaxies and high velocity clouds. This work is part of the legacy aspect of the survey. The catalog is made available to the community so that people can use the information about the hydrogen content of that part of the sky in future scientific work.
Sabrina‘s paper also includes a catalog but is focused on examining the Leo Group. The Leo Group is a relatively nearby collection of galaxies. This means that lots of small galaxies were found in this region that would be too faint to see if they were further away. Sabrina also found a number of small galaxies that had a substantial portion of their mass in gas, but are so faint optically that they hadn’t been found in previous optical searches. Since the Leo Group is a bound collection of galaxies, Sabrina was able to look at the distribution of galaxy masses and compare the number of big galaxies to small galaxies. This helps us understand how structure forms in the universe. (For example, see Ann’s post explaining the HI Mass Function.)