2025-07-01 東京大学
＜関連情報＞
- https://www.s.u-tokyo.ac.jp/ja/press/10842/
- https://iopscience.iop.org/article/10.3847/1538-4357/addab7
M83における高速分子雲 High-velocity Molecular Clouds in M83
Maki Nagata, Fumi Egusa, Fumiya Maeda, Kazuki Tokuda, Kotaro Kohno, Kana Morokuma-Matsui, and Jin Koda
The Astrophysical Journal Published: 2025 June 30
DOI:10.3847/1538-4357/addab7
Abstract
High-velocity clouds (HVCs), which are gas clouds moving at high velocity relative to the galactic disk, may play a critical role in galaxy evolution, potentially supplying gas to the disk and triggering star formation. In this study, we focus on the nearby face-on barred spiral galaxy M83, where high-spatial-resolution, high-sensitivity CO(1–0) data are available. We identified molecular clouds and searched for clouds with velocities deviating by more than 50 km s−1 from the disk velocity field as HVCs. A total of 10 HVCs were detected—9 redshifted and 1 blueshifted—clearly highlighting an asymmetry in their velocity distribution. These HVCs have radii of 30–80 pc, masses on the order of 105 M⊙, and velocity dispersions of 3–20 km s−1, displaying a tendency toward higher velocity dispersion compared to disk molecular clouds in M83. Most of the HVCs do not overlap with the candidates of supernova remnants, and the energy needed to drive HVCs at such high velocities exceeds single supernova energy. Together with the asymmetry in their velocity distribution, we thus conclude that most of the HVCs found in this study are inflow from outside the M83’s disk.
