Broad Fe-emission line in the new X-ray transient XTE J1652-453

Broad iron-emission lines, as detected in X-ray spectra of black-hole binaries, are thought to be reflection signatures of the inner part of the accretion disk and could be used to explore the physical properties of the emitting region close to the black hole. Here we present the recent results of the new X-ray transient and black-hole candidate XTE J1652-453, based on contemporaneous XMM-Newton/RXTE data taken when the source was in the intermediate state a few days before the transition back to the hard state. Its spectrum shows a strong and broad iron-emission line, where the asymmetric profile and the large red wing seem to be indicative for significant relativistic effects. However, before making any firm statement about disk and/or black-hole properties based on iron-line modeling, one needs to seriously consider the contribution of alternative broadening mechanisms, as well as other unknown factors in the relativistic line model and accretion theory. Additionally, properly modeling of the underlying continuum as well as a thorough inspection of the systematic effects caused by the analysis and the instruments, are important concerns that have to be considered