A strong and broad Fe line in the XMM–Newton spectrum of the new X-ray transient and black hole candidate XTE J1652−453


E-mail: hiemstra@astro.rug.nl


We observed the new X-ray transient and black hole candidate XTE J1652−453 simultaneously with XMM–Newton and the Rossi X-ray Timing Explorer (RXTE). The observation was done during the decay of the 2009 outburst, when XTE J1652−453 was in the hard-intermediate state. The spectrum shows a strong and broad Fe emission line with an equivalent width of ∼450 eV. The profile is consistent with that of a line being produced by reflection off the accretion disc, broadened by relativistic effects close to the black hole. The best-fitting inner radius of the accretion disc is ∼4 gravitational radii. Assuming that the accretion disc is truncated at the radius of the innermost stable circular orbit, the black hole in XTE J1652−453 has a spin parameter of ∼0.5. The power spectrum of the RXTE observation has an additional variability component above 50 Hz, which is typical for the hard-intermediate state. No coherent quasi-periodic oscillations at low frequency are apparent in the power spectrum, which may imply that we view the system at a rather low inclination angle.