ALMA Reveals a Cloud-Cloud Collision that Triggers Star Formation in the Small Magellanic Cloud
Abstract
We present the results of Atacama Large Millimeter/submillimeter Array observations in 12CO(1-0) emission at 0.58 × 0.52 pc2 resolution toward the brightest H II region N66 of the Small Magellanic Cloud (SMC). The 12CO(1-0) emission toward the north of N66 reveals clumpy filaments with multiple velocity components. Our analysis shows that a blueshifted filament at a velocity range of 154.4-158.6 km s-1 interacts with a redshifted filament at a velocity of 158.0-161.8 km s-1. A third velocity component at a velocity range of 161-165.0 km s-1 constitutes hub-filaments. An intermediate-mass young stellar object (YSO) and a young pre-main-sequence star cluster have hitherto been reported in the intersection of these filaments. We find a V-shape distribution in the position-velocity diagram at the intersection of two filaments. This indicates the physical association of those filaments due to a cloud-cloud collision. We determine the collision timescale ∼0.2 Myr using the relative velocity (∼5.1 km s-1) and displacement (∼1.1 pc) of those interacting filaments. These results suggest that the event occurred about 0.2 Myr ago and triggered the star formation, possibly an intermediate-mass YSO. We report the first observational evidence for a cloud-cloud collision that triggers star formation in N66N of the low metallicity ∼0.2 Z⊙ galaxy, the SMC, with similar kinematics as in N159W-South and N159E of the Large Magellanic Cloud.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2021
- DOI:
- 10.3847/2041-8213/abdebb
- arXiv:
- arXiv:2101.10711
- Bibcode:
- 2021ApJ...908L..43N
- Keywords:
-
- Star formation;
- Small Magellanic Cloud;
- Interstellar medium;
- H II regions;
- 1569;
- 1468;
- 847;
- 694;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 9 pages, 5 figures. Accepted for publication in Astrophysical Journal Letters (ApJL)