Gas Dynamics and Star Formation in NGC 6822
Abstract
We present H I gas kinematics and star formation activities of NGC 6822, a dwarf galaxy located in the Local Group at a distance of ~490 kpc. We perform profile decomposition of line-of-sight velocity profiles of the H I data cube (42.4″ × 12.0″ spatial, corresponding to ~100 pc; 1.6 km s-1 spectral) taken with the Australia Telescope Compact Array. For this, we use a new tool, the so-called BAYGAUD, which is based on Bayesian analysis techniques, allowing us to decompose a line-of-sight velocity profile into an optimal number of Gaussian components in a quantitative manner. We classify the decomposed H I gas components of NGC 6822 into cool-bulk, warm-bulk, cool-non-bulk, and warm-non-bulk motions with respect to their centroid velocities and velocity dispersions. We correlate their gas surface densities with corresponding star formation rate densities derived using both the GALEX far-ultraviolet and WISE 22 μm data to examine the resolved Kennicutt-Schmidt (K-S) law for NGC 6822. Of the decomposed H I gas components, the cool-bulk component is likely to better follow the linear extension of the K-S law for molecular hydrogen (H2) at low gas surface densities where H I is not saturated.
- Publication:
-
The Astronomical Journal
- Pub Date:
- September 2022
- DOI:
- 10.3847/1538-3881/ac7c1b
- arXiv:
- arXiv:2207.06698
- Bibcode:
- 2022AJ....164...82P
- Keywords:
-
- Interstellar medium;
- Local Group;
- Dwarf irregular galaxies;
- Star formation;
- Galaxy kinematics;
- 847;
- 929;
- 417;
- 1569;
- 602;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 20 pages, 11 figures, 4 tables, accepted for publication in AJ