[Previous] | [Session 10] | [Next]
H.N. Cohn, P.M. Lugger (Indiana University), J.E. Grindlay, P.D. Edmonds, C.O. Heinke (Harvard-Smithsonian CfA), E.P. Rubenstein (Smith College), A.M. Cool (San Francisco State University)
We report preliminary results from a 50 ksec Chandra ACIS-S observation of the center of the collapsed-core globular cluster M30 (NGC 7099). The high blue straggler frequency, large blue-inward color gradient, and significant deficit of red giants in the central region of this cluster all suggest that this is a conducive environment for the production of X-ray binaries by stellar interactions. Previous ROSAT observations detected low-luminosity X-ray emission from the vicinity of the core, but with only about 10'' positional accuracy. Our Chandra observations indicate the presence of at least four discrete low-luminosity (Lx ~ 1031.5-1033 erg/s) sources, all located within 12'' of the dynamical center of the cluster as defined by two HST-based studies. Our preliminary astrometric calibration indicates that two of the sources lie within 1'' of the cluster center, which places them within the very small upper limit on the core radius that has been established by HST-based studies. We are using deep ground-based and HST imaging to determine a tight astrometric alignment between the Chandra and HST images and to test, thereby, our tentative optical identifications of the central Chandra sources. X-ray hardness ratios for the three brightest Chandra sources will constrain the physical nature of the objects. We discuss the implications for the production of low-luminosity X-ray sources in the extreme environment of a highly collapsed cluster core.
This work is supported by NASA grant NAS8-39073.
The author(s) of this abstract have provided an email address for comments about the abstract: cohn@indiana.edu
[Previous] | [Session 10] | [Next]
Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.