Origin of the Scatter in the X-Ray Luminosity of Early-Type Galaxies Observed with ROSAT
Abstract
Statistical properties of X-ray luminosity and temperature are studied for 52 early-type galaxies based on the ROSAT PSPC data. All of the X-ray luminous galaxies show largely extended emission with a radius of a few times 10re, while X-ray faint galaxies do not show such a component. This leads to a division of early-type galaxies into two categories: X-ray extended and X-ray compact galaxies. Except for a few galaxies in dense cluster environments, the luminosity and temperature of X-ray compact galaxies are well explained by a kinematical heating of the gas supplied by stellar mass loss. In contrast, X-ray extended galaxies indicate large scatter in the X-ray luminosity. We discuss the notion that X-ray extended galaxies are the central objects of large potential structures and that the presence or absence of this potential is the main origin of the large scatter in the X-ray luminosity.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 2001
- DOI:
- 10.1086/318389
- arXiv:
- arXiv:astro-ph/0009276
- Bibcode:
- 2001ApJ...547..693M
- Keywords:
-
- Galaxies: Elliptical and Lenticular;
- cD;
- Galaxies: ISM;
- X-Rays: Galaxies;
- X-Rays: ISM;
- Astrophysics
- E-Print:
- 35 pages, including 8 figures, Accepted for publication in ApJ