AAS 199th meeting, Washington, DC, January 2002
Session 25. Black Holes, Dark Matter and X-ray Sources in Extragalactic Systems
Oral, Monday, January 7, 2002, 10:00-11:30am, International Ballroom East

## [25.08] X-ray Source Population in the Elliptical Galaxy NGC 720 as seen with Chandra

T.E. Jeltema, C.R. Canizares (M.I.T.), D.A. Buote (UC Irvine), G.P. Garmire (Penn State)

With a Chandra ACIS-S3 observation, we detect 42 X-ray point sources in the elliptical galaxy NGC 720, including a possible central source. Investigation of the hardness ratios and combined spectra of these sources indicates that most of the sources are soft. However, there is also a population of hard, highly absorbed sources which are generally located at large distances from the center of the galaxy. The overall source distribution is consistent with the ellipticity and position angle of the galaxy, but the sources appear to form several arcs. The source luminosity function is well fit by a broken power-law with a high luminosity slope similar to other early-type galaxies observed with Chandra. However, we find a higher break luminosity of Lb = 11±2 \times 1038 ergs s-1 and a larger number of ultra-luminous sources. Sixteen of the sources in NGC 720 have luminosities above 1039 ergs s-1, similar to the number seen in the Antennae galaxies.

This work was funded by NASA.