AAS 205th Meeting, 9-13 January 2005
Session 32 The Galactic Center
Oral, Monday, January 10, 2005, 10:00-11:30am, Pacific 2/3

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[32.06] An Over-Abundance of Transient X-ray Sources Near the Galactic Center

M. Muno, M. Morris (UCLA), F. Baganoff (MIT)

During five years of Chandra observations, we have identified seven X-ray transients located within 25 pc of the Galactic center. These sources vary in luminosity by more than a factor of 10, and have peak X-ray luminosities greater than 5 \times 1033 erg/s, which strongly suggests that they are accreting black holes or neutron stars. Remarkably, four of these transients lie within only 1 pc of the Galactic center, implying that they are over-abundant by at least a factor of ten per unit stellar mass. There are three possible explanation for this over-abundance of accreting X-ray binaries: (1) they could be high-mass X-ray binaries that formed in situ during recent bursts of star formation, (2) low- or high-mass systems that formed in star clusters that were subsequently captured by the Galactic center, or (3) low-mass X-ray binaries that formed because a cluster of stellar-mass black holes in the central parsec have captured companions through three-body interactions. We discuss future observations that could help distinguish between these possibilities.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.