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Identifying X-ray Sources in Bulge and Disk Galaxies from X-ray Colors

A . H. Prestwich·J. A. Irwin·R. E. Kilgard·M. I. Krauss·A. Zezas·F. Primini·P. Kaaret
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Abstract

The X-ray populations of Local group galaxies have been classified in detail by Einstein, ROSAT and ASCA revealing a mix of binaries, supernova remnants and HII regions. However, these observatories were unable to resolve X-ray sources in galaxies beyond the local group. With Chandra's exquisite spatial resolution we are able to resolve sources in a sample of nearby galaxies. We show that there are highly significant differences in the X-ray colors of sources in bulge and disk systems. These differences can be used as a basis to classify sources as low and high mass X-ray binaries, supernova remnants and supersoft sources. While it is impossible to identify any individual source on the basis of X-ray color alone, the observations presented here suggest that it is possible to separate sources into groups dominated by a single type of source. This classification scheme is likely to be very useful in population studies, where it is crucial to distinguish between different classes of objects.

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A . H. Prestwich, J. A. Irwin, R. E. Kilgard, M. I. Krauss, A. Zezas, F. Primini, P. Kaaret. 2003-06-03. Identifying X-ray Sources in Bulge and Disk Galaxies from X-ray Colors. https://doi.org/10.1086/377366

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