Understanding accretion beyond the Eddington limit: NGC 5204 X-1

It has been suggested that ULXs are in a new superEddington ultraluminous.accretion state, and that they progress through a sequence of three spectralregimes with increasing accretion rate. However, our recent results (Sutton etal. 2013) indicate that inclination is also critical in determining the observedXray properties. These properties can broadly be explained by a massiveradiativelydriven wind that emerges as the Eddington limit is exceeded, andforms a funnel around the black hole axis. Previous observations show NGC 5204X1 straddling the boundary between two ultraluminous regimes, marking it as acritical source in testing this scenario. Here we propose to obtain a furtherfour 20 ks XMMNewton EPIC observations, which will allow us to probe the validity of the proposed model. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]