A direct constraint on the mass of an IMBH candidate in NGC 2276

Although long predicted and searched for, a population of intermediate-mass black holes (IMBHs) has yet to be detected in the local Universe. We have recently published a small sample of luminous ULXs that behave like IMBHs in the low/hard state (Sutton et al. 2012 MNRAS 423 1154). If they are in that state, we expect to see steady radio jets; from these we can directly measure the black hole mass using quasi-simultaneous X-ray & radio observations to place an object on the fundamental plane (see e.g. Merloni et al. 2003 MNRAS 345 1057). In VLA follow-up of the sample an IMBH candidate in NGC 2276 was shown to sit at the centre of two extended radio lobes. We have now been awarded European VLBI network (EVN) observations to attempt to detect its radio core. Here we ask for quasi-simultaneous Chandra observations, necessary to resolve the IMBH candidate from two nearby (within ~5") ULXs and provide the X-ray data point that will allow us to measure the mass of the black hole.