The X-ray properties of normal galaxies
Abstract
An extensive program to study nearby normal galaxies was carried out by various observers using the imaging instruments on the Einstein Observatory; more than 50 such galaxies were detected with 0.5 - 3.0 keV luminosities ranging from 2 × 1038 ergs s-1 to 3 × 1041ergs s-1. The X-ray luminosity of normal galaxies is ~2 × 10-4 of the optical luminosity and shows no strong correlation with morphological type. For the nearest galaxies, (the Large and Small Magellanic Clouds, M31 and M33,) studies, performed with the Observatory, were comparable to the Uhuru survey of the Galaxy. Approximately 30 new SNR were recognized in the Magellanic Clouds as a result. Over 90 sources were detected in M31 of which at least 20 are identified with globular cluster. The numbers of luminous (>1037 ergs s-1) sources detected in the nearest galaxies per unit mass are similar to that found in our own galaxy. Individual X-ray sources in the arms of nearby spirals can be very luminous; seven with luminosities in excess of 1039ergs s-1 have been discovered. The nuclei of some, but not all, normal galaxies are luminous X-ray sources; X-ray activity is not presently predictable from the radio or optical properties of the nucleus.
Permanent Address: Department of Physics, Johns Hopkins University Baltimore, Maryland 21218- Publication:
-
Advances in Space Research
- Pub Date:
- 1982
- DOI:
- Bibcode:
- 1982AdSpR...2i.177L
- Keywords:
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- Galactic Radiation;
- Spaceborne Astronomy;
- X Ray Astronomy;
- Andromeda Galaxy;
- Astronomical Maps;
- Galactic Nuclei;
- Heao 2;
- Magellanic Clouds;
- Supernova Remnants;
- Astrophysics