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Published June 10, 2007 | Published
Journal Article Open

Discovery of hot supergiant stars near the galactic center

Abstract

We report new results of a campaign to find Wolf-Rayet and O (WR/O) stars and high-mass X-ray binaries (HMXBs) in the Galactic center. We searched for candidates by cross-correlating the Two Micron All Sky Survey with a deep Chandra X-Ray Observatory catalog of point sources in the Radio Arches region. Following up with K-band spectroscopy, we found two massive stellar counterparts to CXOGC J174555.3-285126 and CXOGC J174617.0-285131, which we classify as a broad-lined WR star of subtype WN6b and an O Ia supergiant, respectively. Their X-ray properties are most consistent with those of known colliding-wind binaries in the Galaxy and the Large Magellanic Cloud, although a scenario involving low-rate accretion onto a compact object is also possible. The O Ia star lies 4.4 pc in projection from the Quintuplet cluster and has a radial velocity consistent with that of the Quintuplet, suggesting that this star might have escaped from the cluster. We also present the discovery of a B2 Ia supergiant, which we identified as a candidate massive star using 8 μm Spitzer maps of the Galactic center in a region near the known massive X-ray-emitting star CXOGC J174516.1-290315. We discuss the origin of these stars in the context of evolving stellar clusters in the Galactic center.

Additional Information

© 2007 American Astronomical Society. Print publication: Issue 1 (2007 June 10); received 2006 December 29; accepted for publication 2007 March 7. We are grateful to the anonymous referee for very insightful and helpful comments. We also thank Margaret Hanson, Paul Cowther, Fabrice Martins, and Frank Eisenhauer for kindly supplying us with K-band spectra of hot stars for our comparative analysis, and Tetsuya Nagata and Shogo Nishiyama for sharing near-IR photometry data from the IRSF SIRIUS survey. J. C. M. would like to thank Simon Portegies-Zwart for a helpful interchange regarding the dynamical evolution of compact clusters in the Galactic center. This research was supported by an NSF grant (AST 04-06816).

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August 22, 2023
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