AAS 197, January 2001
Session 111. Galaxy Morphology and Structure
Display, Thursday, January 11, 2001, 9:30-4:00pm, Exhibit Hall

## [111.11] {\em Chandra} Observations of the X-Ray Point Source Population in Centaurus A

J.M. Kregenow (Wittenberg University), R.P. Kraft, C. Jones, W.R. Forman, S.S. Murray (CFA), High Energy Division

We present the results from a study of the X-ray point source population in two {\em Chandra} observations of the nearby radio galaxy Centaurus A (NGC 5128). Using a wavelet decomposition detection algorithm, we detect 246 individual point sources above a limiting flux of 1.34\times10-15erg/cm2s, which corresponds to a luminosity of 1.96\times1036 erg/s. Of the 246 sources detected, 82 are detected in both data sets where the fields of view overlap. We positively identify 8 foreground stars in our observations, and estimate approximately 15% to 20% of the sources to be background AGN not associated with Centaurus A. The remaining ~200 sources, likely associated with the galaxy, are probably X-ray binaries and supernova remnants. We identify 11 with known globular clusters, and 41 as possible transient or variable sources. We find that the population of X-ray point sources in Centaurus A, a merged elliptical and spiral galaxy with an active nucleus, is not significantly different than that of M31 in both spatial distribution and luminosity range. We also detect in one observation a possible super-Eddington X-ray transient previously detected by ROSAT.

This project was supported by NASA contract NAS8-38248, and the observations were made as part of the HRC GTO program. The research was conducted, in part, through the Harvard-Smithsonian CfA Undergraduate Summer Intern Program as part of the NSF REU program.