Trying to figure out the shape of a galaxy we are inside is a bit challenging. Our view is impeded by gas and dust, and it is often hard to make a three-dimensional sense of our two-dimensional images. These struggles get even more difficult when we are trying to make sense of the structures within gas clouds – those streams and shells of compressed gas that trace out the disk of our Milky Way.
In a new paper in Astronomy & Astrophysics with first author JD Soler, researchers let computers take their turn in understanding our galaxy.
High-resolution Very Large Array (VLA) images of the distribution of hydrogen gas were fed into computer vision software that was coded to look for the slight overdensities that mark areas that have experienced shocks or been drawn together with gravity. The software was able to identify a 2000 lightyear long hydrogen lane through the disk of the galaxy that the team named Magdelena after the longest river in Colombia.
According to researcher Jonas Syed: [Magdalena] could be the largest known coherent object in the Milky Way. In recent years, astronomers have studied many molecular filaments, but Maggie seems to be purely atomic. Because of its fortunate position in the Milky Way, we are lucky to have been able to spot it.
In addition to this and many other expected structures laying parallel to the disk of the galaxy, the team also found bizarre structure pointing out of the galaxy. JD Soler explains: Like in the spinning pizza dough, we expected that most of the filaments would be parallel to the plane and stretched by the rotation. But when we found many vertical filaments around regions known for their high star formation activity, we knew we were onto something. Some process must have been blowing material off the galactic plane.
Continued analysis of these structures is going to allow the history of our galaxy to be observed through the echoing shockwaves of now-dead stars and regions of star formation. This research is just the start, and I can’t wait to see what else they find thanks to a little help from computer vision.
“The History of Dynamics and Stellar Feedback Revealed by the HI Filamentary Structure in the Disk of the Milky Way,” J. D. Soler, H. Beuther, J. Syed, Y. Wang et al., 2020 Oct. 21, Astronomy & Astrophysics (preprint on arxiv.org)
“The HI/OH/Recombination Line Survey of the Inner Milky Way (THOR): Data Release 2 and HI Overview,” Y. Wang, H. Beuther, M. R. Rugel, J. D. Soler et al., 2020 Feb. 12, Astronomy & Astrophysics (preprint on arxiv.org)