ULX P13 in NGC 7793: A super-Eddington accreting black hole

Optical observations of P13 in NGC 7793 allowed us to determine for the first time the mass of the black hole in an ULX, clearly indicating super-Eddington accretion. The donor is a B8I star in an eccentric orbit. Swift XRT monitoring revealed a likely eclipse as well as an extended faint state. Our serendipitous faint state Chandra spectrum shows evidence of redshifted iron line which we tentatively assign to a jet. We propose to obtain high S/N spectra of the bright, faint and eclipse states. Spectral properties of the bright state will define the key signatures of super-critical accretion. Eclipse observation will allow us to constrain the orbit and to possibly reveal evidence of bulk motion. Faint state observations will likely provide the first direct detection of a jet in an ULX.