Understanding two new extreme X-ray sources

Our optical identification campaign of hard X-ray sources in the XMM-Newton Galactic Plane Survey (XGPS) has revealed two exceptional objects. First, source XGPS-3 is identified with a heavily absorbed very bright infrared source which could be a star as luminous as eta Carina. Second, XGPS-25 has all the features expected from a low-mass X-ray binary whose X-ray emission is strongly shielded by the accretion disc and if confirmed, would be the first very high inclination accretion disc corona known to date. The present proposal aims at obtaining high quality X-ray spectra and time series which will help us to clarify the exact nature of these two objects.