Central radio sources in spiral galaxies. Starburst or accretion.
Abstract
The mechanism of radio emission from the central 1-kpc-radius regions of galaxies is investigated on the basis of 20-min 2, 6 and 20-cm observations obtained with the VLA during March 1981, for 16 galaxies. The data are presented in tables, maps, and graphs and compared with published data on a larger sample. The individual galaxies are characterized in detail, and the radio morphology of the sample is discussed in terms of accretion and starburst models. The central sources are found to consist of combinations of three component types: flat-spectrum compact core sources typical of bulge-dominated and elliptical galaxies, 10-100-pc nuclear sources occurring in spiral galaxies, and extranuclear components of various shapes. The 6-cm temperatures of the components are given as greater than 100,000 K, 100-10,000 K, and less than 1000 K, respectively. While most extranuclear-component emission is consistent with current starburst models, major revisions are required to explain the nuclear sources, and more exotic nonstarburst models are needed for the core sources.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1984
- Bibcode:
- 1984A&A...134..207H
- Keywords:
-
- Galactic Nuclei;
- Galactic Radio Waves;
- Galactic Structure;
- Radio Galaxies;
- Spiral Galaxies;
- Starburst Galaxies;
- Supernovae;
- Accretion Disks;
- Astronomical Models;
- Centimeter Waves;
- Elliptical Galaxies;
- Radio Spectra;
- Astrophysics