AAS 205th Meeting, 9-13 January 2005
Session 92 Ellipticals and Early Types
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[92.10] Multi-Epoch {\em Chandra} Observations of the X-ray Point Source Population of Centaurus A

K. E. Whitaker (University of Massachusetts - Amherst), R. P. Kraft, C. Jones, W. R. Forman, S. S. Murray (Harvard/Smithsonian Center for Astrophysics), M. J. Hardcastle (University of Hertfordshire), D. M. Worrall (University of Bristol)

We present preliminary results from four {\em Chandra} observations of the X-ray point source population of the nearby X-ray-gas poor elliptical galaxy Centaurus A. These four observations, two with ACIS-I and two with ACIS-S, were taken over a period of four years. The total observation time is ~160 ks. Results from the first two of these observations have been published previously (Kraft et al., 2001). We detected 353 point sources, the vast majority of which are associated with the galaxy. The limiting luminosity at the center of the galaxy is ~6\times1035 ergs s-1, and our observations are complete and unbiased above a luminosity of ~1037 ergs s-1. Above the completeness limit, only ~10% of the sources are statistically likely to be background AGN and galaxies. The position, flux, and luminosity of each detection is catalogued. We have correlated the positions of X-ray sources with globular clusters and find ~30% of the sources within 4' of the nucleus to be associated with GCs. We perform spectral analysis on the bright sources, and compute luminosity functions of the X-ray point source populations for each epoch. Although ~25% of the sources are variable between any two observations, the integral luminosity functions are unchanged. This suggests that any given snapshot of the point source population of early galaxies is a representative sample. The integral luminosity function is well described by a powerlaw with index 1.1±0.2, although there is evidence that the LF steepens above ~3\times1038 ergs s-1. This work was supported by NASA contract NAS8-38248.

The author(s) of this abstract have provided an email address for comments about the abstract: kwhitake@student.umass.edu

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© 2004. The American Astronomical Society.