Brightness profiles of the cores of bulges and elliptical galaxies.
Abstract
High-resolution surface photometry of the cores of bulges and elliptical galaxies, obtained at a scale of 0.22 arcsec/pixel and seeing of 0.45-1.0 arcsec, are examined. Core profiles which conform to the projected isothermal model are found only in a few elliptical galaxies, mostly the first-ranked galaxies in rich clusters. Most ellipticals were found to have cores which are nonisothermal by a consistent small amount. Moreover, bulges of the disk galaxies have profiles that rise steeply toward the center. The absolute magnitudes of the isothermal ellipticals, nonisothermal ellipticals, and bulges were found to be -22.8 + or - 0.4, -21.4 + or - 0.3, and -19.7 + or - 0.5, respectively. The trend toward more compact nuclei observed in smaller galaxies suggests that small bulges and ellipticals formed with more dissipation than large ones.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 1985
- DOI:
- 10.1086/184463
- Bibcode:
- 1985ApJ...292L...9K
- Keywords:
-
- Astronomical Photometry;
- Brightness Distribution;
- Elliptical Galaxies;
- Galactic Evolution;
- Galactic Nuclei;
- Galactic Structure;
- Cassegrain Optics;
- Disk Galaxies;
- High Resolution;
- Luminosity;
- Astrophysics