Hintze Centre for Astrophysical Surveys

Abstract:

Over the last 25 years ∼75% of the low-mass X-ray binary X-ray transients have been shown to contain black-hole compact objects, based on optical spectroscopy of their kinematics when in quiescence. Because many of these systems are extremely faint in quiescence and unobservable, we have utilised the method of studying them when in X-ray outburst that exploits the fluores- cence features produced by X-ray irradiation of the donor's inner face, thereby allowing us to track the motion of the donor. Such outbursts are unpredictable and hence these studies must necessarily be through Target-of-Opportunity programs, and hence are ideal for SALT for accessible targets. Here we report on our SALT ToO studies of two transients, both believed to contain black holes and both at high galactic latitude.