Date Presented:

2009/09/1

Abstract:

Using Chandra, XMM-Newton and optical photometric and spectroscopic catalogs we study the young (<100 Myr) X-ray binary populations of the Small Magellanic Cloud, which at ˜60 kpc is our second nearest star-forming galaxy. In particular, we investigate the importance of Be/X-ray binaries as a dominant component of young X-ray binary populations, based on a study of the connection between X-ray source populations and their parent stellar populations. We find that a significant number of Be/X-ray binaries and/or pulsars are connected with a burst of star formation ˜25-60 Myr ago, while regions with weak star-formation rate at ˜42 Myr, such as the SMC Wing, are deficient in Be/X-ray binaries. We argue that the very strong similarity between the age of maximum occurence of Be stars and the age of the parent populations of X-ray binaries in the Small Magellanic Cloud indicates that the Be phenomenon plays a significant role in the number of X-ray binary populations in this age range. Finally, based on the spatial correlation between the star-formation activity and the X-ray binaries, we set a limit on their kick velocity of ˜15-20 km/s, while there is strong indication for velocities of even a factor of two lower, and we estimate a Be/X-ray binary production rate of ˜1 system per 10^{-6} M_{⊙}/yr.

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