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" x 12.0" spatial, corresponding to ~ 100 pc; 1.6 km s${}^{-1}$ spectral) taken with the Australia Telescope Compact Array (ATCA). 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 $\mu$m 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 (H${}_2$) at low gas surface densities where H I is not saturated.

20 pages, 11 figures, 4 tables, accepted for publication in AJ

References in corpus (16)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• The GALEX Ultraviolet Atlas of Nearby Galaxies
• Star formation efficiency in galaxy interactions and mergers: a statistical study
• High-resolution dark matter density profiles of THINGS dwarf galaxies: Correcting for non-circular motions
• A complete 12CO 2-1 map of M51 with HERA: I. Radial averages of CO, HI, and radio continuum
• Revisiting the Integrated Star Formation Law. Paper I: Non-Starbursting Galaxies
• Revisiting the Integrated Star Formation Law. II. Starbursts and the Combined Global Schmidt Law
• Physical Properties of Molecular Clouds at 2 parsec Resolution in the Low-Metallicity Dwarf Galaxy NGC 6822 and the Milky Way
• The spatially resolved Kennicutt-Schmidt relation in the HI dominated regions of spiral and dwarf irregular galaxies
• The Nature of Infrared Emission in the Local Group Dwarf Galaxy NGC 6822 As Revealed by Spitzer
• The Molecular Interstellar Medium of the Local Group Dwarf NGC6822
• L1188: a promising candidate of cloud-cloud collision triggering the formation of the low- and intermediate-mass stars
• A Catalog of Holes and Shells in the Interstellar Medium of the LITTLE THINGS Dwarf Galaxies
• A panoramic view of the Local Group dwarf galaxy NGC 6822
• Robust profile decomposition for large extragalactic spectral-line surveys
• HI Kinematics, Mass Distribution, and Star Formation Threshold in NGC 6822, using the SKA pathfinder KAT-7

Cited by in corpus (4)

• The Karl G. Jansky Very Large Array Local Group L-band Survey (LGLBS)
• WALLABY Pilot Survey: HI gas kinematics of galaxy pairs in cluster environment
• Estimating the evolution and the content fractions of baryonic gas for Luminous Infrared Galaxies
• Recent Developments on the HI Gas of Low-Redshift Galaxies Seen by the 21cm Emission Lines