Probing the Origin of the Intermediate Mass Black Hole ESO 243-49 HLX-1
Abstract
While it is widely accepted that most (perhaps all) galaxies host a supermassive black hole in their centers, how these black holes form is not understood. Two leading theories propose that they are formed either from hierarchical mergers of stellar mass black holes, or from the growth (through accretion and/or mergers) of primordial black holes formed through the direct collapse of ~104-6 M⊙ gas clouds shortly after the Big Bang. Both theories predict the existence of intermediate mass black holes with masses in the range of ~102-5 M⊙. Intermediate mass black holes are also important as they may have contributed significantly to the epoch of reionization, could constitute catalysts of dark matter annihilation in galaxy halos, and are predicted to be strong sources of gravitational wave radiation. However, observational evidence for the existence of black holes in this mass range has until recently been lacking. Arguably, the best candidate intermediate mass black hole is currently the hyperluminous X-ray source HLX-1 in the S0a galaxy ESO 243-49, with a maximum X-ray luminosity of 1.3 × 1042 erg s-1, ~1,000 times above the Eddington limit for a 10 M⊙ black hole. The current mass estimates (derived from Eddington scaling, modeling the thermal emission from the accretion disc, and from limits obtained from the detection of ballistic jets) put the black hole between 9 × 103 to 9 × 104 M⊙. Here I will present the latest results of broadband spectral energy distribution modeling making use of observations of HLX-1 with the HST, VLT, XMM-Newton, and Swift telescopes. With these data we attempt to ascertain the nature of the environment around HLX-1 and thus determine the origin of this unique object.
- Publication:
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AAS/High Energy Astrophysics Division #13
- Pub Date:
- April 2013
- Bibcode:
- 2013HEAD...1340308F