Underluminous X-ray transients near the Galactic Center
Abstract
We present the latest results from our studies of a sub-class of X-ray transients, whose members display anomalously low peak luminosities of ∼ 1034-35 erg s-1 (2-10 keV). A large fraction of these underluminous transients is expected to harbor accreting compact objects. We study the outburst behavior of several transients near the Galactic Center with the sensitive X-ray satellites Chandra, XMM-Newton and Swift. We find a wide range in outburst durations (days to years) and duty cycles (∼ 5% - 25%), from which we estimate long-term time-average ˙ accretion rates of M ∼ 10-14 - 10-11 M yr-1 . We will discuss the difficulties of the disc instability model to account for the observed underluminous outbursts and how these systems can be explained in terms of binary evolution. These underluminous X-ray transients probe accretion rate regimes (both long-term and in outburst) previously uncharted for compact objects.
- Publication:
-
37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37..679D