A statistical analysis of the Einstein normal galaxy sample. I. Spiral and irregular galaxies.
Abstract
The results of a statistical analysis of 48 spiral and irregular galaxies observed with the Einstein Observatory are reported. It is found that the X-ray luminosity is not directly correlated with the mass of the galaxies, but is strongly correlated with the blue luminosity. This suggests that most X-ray sources, including low-mass binaries, are binary systems belonging to both old disk and young arm Population I components. A real bulge population of X-ray sources exists that can contribute significantly to the X-ray luminosity of early-type spirals. The X-ray emission from a sample of 29 relatively isolated, normal elliptical and S0 galaxies is also studied, and the results are compared to those for the above sample to investigate the origin of the X-ray emission in early-type galaxies and the possible emission mechanisms. The influence of a powerful radio source and the onset of nuclear activity are also examined.
- Publication:
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The Astrophysical Journal
- Pub Date:
- September 1985
- DOI:
- Bibcode:
- 1985ApJ...296..430F
- Keywords:
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- Irregular Galaxies;
- Spiral Galaxies;
- Statistical Analysis;
- X Ray Sources;
- Astronomical Observatories;
- Galactic Nuclei;
- Samples;
- Star Distribution;
- Astrophysics