2012/11/05 by N. A. Webb, D. Barret, Webb, N. A. +34
Engineering · Physics and Astronomy · #Astrophysical Phenomena and Observations #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #High Energy Astrophysical Phenomena (astro-ph.HE) #Mechanics and Biomechanics Studies #astro-ph.CO #astro-ph.HE
paper · pdf · doi:10.48550/arxiv.1211.0831
5 pages, three figures, to appear in the proceedings of the SF2A 2012
arxiv created 2012/11/05 · openalex publication_date 2012/11/05 · arxiv updated 2012/11/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Ultra Luminous X-ray (ULX) source HLX-1 in the galaxy ESO 243-49 has an observed maximum unabsorbed X-ray luminosity of 1.3e42 erg/s (0.2-10.0 keV). From the conservative assumption that this value exceeds the Eddington limit by at most a factor of 10, the minimum mass is then 500 solar masses. The X-ray luminosity varies by a factor of 40 with an apparent recurrence timescale of approximately one year. This X-ray variability is associated with spectral state transitions similar to those seen in black hole X-ray binaries. Here we discuss our recent modelling of all the X-ray data for HLX-1 and show that it supports the idea that this ULX is powered by sub- and near Eddington accretion onto an intermediate mass black hole. We also present evidence for transient radio emission which is consistent with a discrete jet ejection event as well as comment on the nature of the environment around HLX-1 in light of recent Hubble Space Telescope photometry.