Date Presented:

2007/05/1

Abstract:

We discuss the results from the optical study of the X-ray sources detected in our Chandra survey of the central region of the Small Magellanic Cloud. Based on the OGLE-II and MCPS optical photometric catalogs we propose the most likely counterpart for 113 X-ray sources, 32 of which are identified with early type counterparts (of OB spectral type based on their position in color-magnitude diagrams). Optical spectroscopy of these counterparts with the 2dF spectrograph (AAT) reveals 13 new Be-XRBs in the SMC "bar". We estimate that these Be-XRBs have an age of 15-85 Myr, consistent with the typical age of Be stars. We also examine the "overabudance" of Be-XRBs in the SMC fields covered by Chandra, in comparison to the Milky Way, and we show that there is residual excess, even after accounting for the higher star formation rate of the SMC. This excess can be attributed to the lower metallicity of the SMC. Finally, we present a preliminary study of the parent stellar populations of these X-ray binaries based on deep IMACS observations.

This work was supported by NASA LTSA grant NAG5-13056, and NASA grant G02-3117X.

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