AAS 204th Meeting, June 2004
Session 5 Eclipsing Binaries and Friends
Poster, Monday, May 31, 2004, 9:20am-6:30pm, Ballroom

[Previous] | [Session 5] | [Next]

[5.14] A Comparison Between Spectral Properties of ULXs and Luminous X-ray Binaries

C. T. Berghea, E. J. M. Colbert (CUA), T. P. Roberts (Leicester)

What is special about the 1039 erg~s-1 limit that is used to define the ULX class? We investigate this question by analyzing Chandra X-ray spectra of 71 X-ray bright point sources from nearby galaxies. Fifty-one of these sources are ULXs (LX(0.3-8.0~keV) \ge 1039 erg~s-1), and 20 sources (our comparison sample) are less-luminous X-ray binaries with LX(0.3-8.0~keV)~= 1038-39 erg~s-1. Our sample objects were selected from the Chandra archive to have \ge1000 counts and thus represent the highest quality spectra in the Chandra archives for extragalactic X-ray binaries and ULXs. We fit the spectra with one-component models (e.g., cold absorption with power-law, or cold absorption with multi-colored disk blackbody) and two-component models (e.g. absorption with both a power-law and a multi colored disk blackbody). A crude measure of the spectral states of the sources are determined observationally by calibrating the strength of the disk (blackbody) and coronal (power-law) components. These results are then use to determine if spectral properties of the ULXs are statistically distinct from those of the comparison objects, which are assumed to be ``normal'' black-hole X-ray binaries.

The author(s) of this abstract have provided an email address for comments about the abstract: 79berghea@cua.edu

[Previous] | [Session 5] | [Next]

Bulletin of the American Astronomical Society, 36 #2
© YEAR. The American Astronomical Soceity.