Chandra Observations of the Stellar Populations and Diffuse Gas in Nearby Galaxies

Abstract

We present Chandra observations of two star-forming galaxies (M82 and the Antennae) and three starburst/AGN composite galaxies (NGC1808, NGC6240, NGC7331). In both star-forming galaxies we detect a large number of sources with diverse properties. Some of them can be identified as X-ray binaries, based on their variability and spectra. However, there is a significant number of very soft and/or extended sources which could be supernova remnants. These observations confirm previous indications that there is a population of sources with X-ray luminosities much higher than the Eddington limit for a neutron star, suggesting that these objects are abundant in star-forming galaxies. We find the the X-ray luminosity functions of the discrete sources in these two galaxies are very similar. In the case of the composite galaxies we find that the AGN does not dominate their X-ray emission. A significant fraction of the emission from these objects is extended but there are also X-ray sources associated with circumnuclear star-formation.

6 pages, 6 figures, To appear in the proceedings of the conference "The Central kpc of Starburst and AGN", APS Conference Series (Vol. 249) Knapen J.H., Beckman J.K., Shlosman I., Mahoney T.J. Eds uses newpasp.sty (included)