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[29.01] The L_{\rm X} > 10³⁰~erg~s^-1 Source Population of Three Globular Clusters

D. Pooley, W.H.G. Lewin (MIT), F. Verbunt (Astron. Inst., Netherlands), D.W. Fox (MIT), B. Margon (Univ. Washington), V.M. Kaspi (McGill Univ.), M. van der Klis (Astron. Inst., Netherlands), J. Miller (MIT)

We report the results of our Chandra ACIS-S3 observations of the globular clusters NGC~6752 (30~ksec), NGC~6440 (25~ksec), and NGC~6121 (25~ksec). We present positions and spectra for the sources in NGC~6752 and preliminary results from the other two clusters. The four sources detected in NGC~6752 with the ROSAT HRI are resolved into 13 sources by Chandra. The spectra of all five sources with greater than 200 counts are nonthermal and are well fit as power laws (plus absorption) with photon indices in the range 1.3--1.8. We compare our X-ray source positions with the positions of the two CVs identified by Grindlay and collaborators on the basis of HST observations of the cluster. If our positions are accurate to better than one arcsec, as suggested by cross-identification of two bright foreground stars with Chandra sources, then none of our 13 sources is coincident with either CV. We discuss the ramifications of our results for the nature of the low-luminosity globular cluster X-ray source population.

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