Broadband X-ray Spectroscopy of the Unique ULX P13 in NGC7793

We request an XMM (50 ks) + NuSTAR (100 ks) ToO observation of the ULX P13 inNGC7793 during its ultraluminous regime (Lx > 2e39 erg/s). The dynamical massconstraint available for this source requires it to be superEddington at theseluminosities, making it a key laboratory for understanding this exotic mode ofaccretion. These observations will provide the first hard Xray detection ofthis source, and provide a vital point of comparison with a knownsuperEddington accretor for the rest of the ULX population with broadband Xrayobservations, which is currently missing. P13 is currently the only source thatcan provide this link. Our ToO will be triggered by the 12x1 ks Swift monitoringadditionally requested as part of this proposal. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]