Aperture Synthesis Observations of HI and CO in the Early Type Starburst Galaxy NGC 3928
Abstract
Aperture synthesis observations of the 21 cm H I and the ^12^C0 J = 1 _0 lines with spatial resolutions of 24" X 22" and 11" X 6", respectively, are presented to study the gas distribution and kinematics in the blue compact early type starburst galaxy NGC 3928. The CO emission is partially resolved and is confined to a rotating disk with FWHM~11" in the nucleus of the galaxy. There is evidence to suggest that CO (and possibly H I) is deficient in the central few hundred pc. The average H_2_ surface density of the molecular disk of ~400M_sun_/pc^2^ is much higher than found in the Galactic molecular ring. The H I emission is centrally concentrated and most of the emission is within its de Vaucouleurs' radius, features not shared by most of the gas-rich S0/Sa galaxies studied so far. The H I displays a regular velocity field and is consistent with a disk in nearly solid body rotation out to r~3.7 kpc if no warp occurs within the optical radius, suggesting a dark halo surrounding the galaxy. There is good agreement between the kinematics of the CO and that of the H I where the two overlap in the inner part. The relatively unperturbed gas morphology argues against a recent interaction/merger being the cause of the nuclear starburst.
- Publication:
-
The Astronomical Journal
- Pub Date:
- January 1994
- DOI:
- 10.1086/116836
- Bibcode:
- 1994AJ....107...90L
- Keywords:
-
- Carbon Monoxide;
- Compact Galaxies;
- Disk Galaxies;
- Emission Spectra;
- Galactic Halos;
- H I Regions;
- Starburst Galaxies;
- Synthetic Apertures;
- Galactic Evolution;
- Galactic Rotation;
- Galactic Structure;
- Spatial Resolution;
- Spectrum Analysis;
- Star Formation;
- Velocity Distribution;
- Astrophysics;
- GALAXIES: INDIVIDUAL: NGC 3928;
- GALAXIES: STARBURST;
- GALAXIES: ABUNDANCES