Evidence for IMBHs from tidal disruption events and ultra luminous X-ray sources
Abstract
Observational evidence for intermediate mass black holes has been weak. Two promising environments to search for such objects include the centres of low mass galaxies and in the most luminous of the ultra lumimnous X-ray sources, which are simply defined as non-nuclear extra-galactic X-ray point sources that exceed the Eddington luminosity (where the radiation pressure is balanced by the gravitational pressure) for a stellar mass black hole. This talk will cover the tidal disruption event of a star that approached the central black hole in the galaxy IC 4765-f01-1504 and which was subsequently accreted. Through fitting of the X-ray spectrum and analysis of the X-ray lightcurve, the black hole mass has been determined to be between 1 x 10^5 and 1 x 10^6 solar masses (M). This mass is also consistent with the black hole mass versus bulge luminosity relationship. I will also cover the serendipitous discovery of an X-ray source apparently associated with the galaxy ESO 243-49, situated at 95 Mpc. Follow-up spectroscopy of the optical counterpart confirmed the association. Using the maximum X-ray luminosity of 1.1 x 10^42 erg s-1 (0.2-10.0 keV) and the conservative assumption that this value exceeds the Eddington limit by at most a factor of 10, implies a minimum mass of 500 M. Modelling of the X-ray spectra implies a mass of the order 1 x 10^4 M and recent radio observations provide an upper limit on the mass of 1 x 10^5 M. This source, now known as HLX-1, is therefore a very strong intermediate mass black hole candidate.
- Publication:
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APS April Meeting Abstracts
- Pub Date:
- March 2012
- Bibcode:
- 2012APS..APR.C3002W