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 2MASS catalog with a deep Chandra catalog of X-ray 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 sub-type 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 micron 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.

21 pages, 5 figures, accepted for publication in the Astrophysical Journal

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Cited by in corpus (21)

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• A Catalog of X-ray Point Sources from Two Megaseconds of Chandra Observations of the Galactic Center
• HST Paschen-alpha Survey of the Galactic Center: Data Reduction and Products
• Near-infrared counterparts to Chandra X-ray sources toward the Galactic Center. II. Discovery of Wolf-Rayet stars and O supergiants
• HST/NICMOS Paschen-alpha Survey of the Galactic Center: Overview
• Isolated Wolf-Rayet Stars and O Supergiants in the Galactic Center Region Identified via Paschen-alpha Excess
• Red Eyes on Wolf-Rayet Stars: 60 New Discoveries via Infrared Color Selection
• Isolated massive stars in the Galactic center: The dynamic contribution from the Arches and Quintuplet star clusters
• Near-Infrared Counterparts to Chandra X-ray Sources toward the Galactic Center. I. Statistics and a Catalog of Candidates
• A Multiwavelength Study of Evolved Massive Stars in the Galactic Center
• Discovery of a Luminous Blue Variable with an Ejection Nebula Near the Quintuplet Cluster
• 2D kinematics of massive stars near the Galactic Center
• J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare
• Constraining the population of isolated massive stars within the Central Molecular Zone
• The Mid-Infrared Colors of the ISM and Extended Sources at the Galactic Center
• Characterizing Wolf-Rayet Stars in the Near and Mid Infrared
• Suzaku X-Ray Spectroscopy of a Peculiar Hot Star in the Galactic Center Region
• The binary nature of the Galactic Centre X-ray source CXOGC J174536.1-285638
• Three New Galactic Center X-ray Sources Identified with Near-Infrared Spectroscopy
• Near-infrared counterparts of Chandra X-ray sources toward the Galactic Center
• Comparison of 3.6 - 8.0 Micron Spitzer/IRAC Galactic Center Survey Point Sources with Chandra X-Ray Point Sources in the Central 40x40 Parsecs