2024/06/03
Keio University
Nobeyama Radio Observatory, National Astronomical Observatory of Japan
A research team led by Hiroki Yokozuka (who completed his master's degree in 2022) from the Graduate School of Science and Technology at Keio University and Professor Tomoharu Oka from the university's Faculty of Science and Technology has discovered a molecular cloud (CO 16.134–0.553) with an unusually broad velocity width (approximately 40 km s –1 ) in a relatively quiescent region of the Milky Way. This molecular cloud possesses enormous kinetic power and shows signs of having been hit by a strong shock wave in the past, yet it has no clear associated energy source. A detailed examination of past wide-area data revealed that CO 16.134–0.553 is part of a slightly larger expanding spherical shell structure of molecular gas, that a giant atomic gas "cavity" exists in that region of the Milky Way, and that a long, straight "filament" exists below the Milky Way. These spatial structures indicate that some object that fell from the halo of the Milky Way galaxy passed through the disk of the Milky Way galaxy at high speed. Since there is no bright object at the tip of the filament, it is highly likely that the object that fell from the halo is a "dark matter subhalo" that failed to become a dwarf galaxy or a globular cluster.
The results of this research were published in the March 14, 2024 issue of the American astrophysics journal " The Astrophysical Journal ".
For the full press release, please see below.