Searching for Imbh Candidates among Ultraluminous X-Ray Sources
Abstract
A sub-sample of bright Ultraluminous X-ray Sources (L ~ (1-5)e40 erg/s)shows peculiar power-law like spectra, with no high energy turn-off andshort-term variability at the level of ~10%. These sources may possiblyhost Intermediate Mass Black Holes (IMBHs) in a low/hard state, althoughtheir apparently flat spectral shape may be the effect of poor countingstatistics. Here we propose new simultaneous medium- deep XMM-Newton andNuSTAR observations of three such objects to find evidence either of thetypical X- ray properties (power-law spectra and short term variability)that should characterize sub-Eddington accretion onto an IMBH or of thecharacteristic spectral curvature of the Ultraluminous state.
- Publication:
-
XMM-Newton Proposal
- Pub Date:
- October 2014
- Bibcode:
- 2014xmm..prop..117P