Accretion disk parameters in HLX-1

Abstract

We estimate the outer radius of the accretion disk in HLX-1 from its optical brightness and from the exponential timescale of the decline in the X-ray lightcurve after an outburst. We find that the disk is an order of magnitude smaller than the semimajor axis of the orbit. If the disk size is determined by the circularization radius near periastron, the eccentricity of the binary system must be >~ 0.95. We report on the discovery of H-alpha emission during the 2012 outburst, with a single-peaked, narrow profile (consistent with a nearly face-on view), and a central velocity displaced by ~490 km/s from that of the host galaxy.

4 pages, 111 KB. To appear in the Proceedings of IAU Symposium 290, "Feeding compact objects: accretion on all scales", Beijing, 20-24 Aug 2012. This paper contains a summary of Soria (2013), arXiv:1210.4169, plus new preliminary VLT results

References in corpus (9)

• Radio Detections During Two State Transitions of the Intermediate Mass Black Hole HLX-1
• X-ray Variability and Hardness of ESO 243-49 HLX-1: Clear Evidence for Spectral State Transitions
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• Interacting Binaries with Eccentric Orbits II. Secular Orbital Evolution Due To Non-Conservative Mass Transfer
• A Young Massive Stellar Population Around the Intermediate Mass Black Hole ESO 243-49 HLX-1
• Optical counterpart of HLX-1 during the 2010 outburst
• Mass transfer during low mass X-ray transient decays
• A minor merger scenario for the ultraluminous X-ray source ESO 243-49 HLX-1
• Eccentricity of HLX-1