PI: Nathalie Degenaar, Univ. of Amsterdam, N.D.Degenaar@uva.nl
Address: Astronomical Institute, Kruislaan 403, Amsterdam 1098SJ, Netherlands
CoI: Dipankar Maitra, Univ. of Amsterdam
CoI: Rudy Wijnands, Univ. of Amsterdam
Title: Identification of Optical/near-IR Counterparts of very-faint X-ray Transients
Abstract: Transiently accreting compact objects (neutron stars and black holes) spend most of their time in a dim, quiescent state, but occasionally they experience bright X-ray outbursts during which their X- ray luminosity increases by more than a factor of 100. The brightest X- ray transients have been known and extensively studied since the beginning days of X-ray astronomy. However, in the past decade it became clear that there exists a group of X-ray transients that display anomalously low X-ray luminosities during outburst. The nature of these systems is not understood, but they might harbor exotic manifestations of accreting neutron stars and black holes. For most of these very- faint systems no optical/IR counterpart has been identified so far. We propose X-ray triggered optical/IR target-of-opportunity observations of these enigmatic X-ray transients during outburst, using the CTIO/SMARTS 1.3m telescope, to search for their optical/IR counterparts. With the proposed observations we aim to study not only the nature of individual systems, but also the properties of the population of very-faint X-ray transients as a whole.
National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360