Constraining the Black Hole Mass in the Most Luminous ULX

Following a search for soft-spectrum sources in the 2XMM catalogue, we have identified the most luminous ultra-luminous X-ray (ULX) source currently known. The extreme luminosity and steep power law spectrum of this source are most likely produced by accretion onto an intermediate mass black hole. We wish to perform a single observation of this source with the XMM-Newton EPIC cameras and the OM in order to constrain the temperature of the inner regions of the accretion disc, search for quasi-periodic oscillations, investigate the long-term variability, and search for an ultra-violet counterpart. By achieving these aims we will be able to accurately constrain the mass of the black hole, providing conclusive evidence for the existence of intermediate mass black holes.