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We report on the analysis of the broad Fe Kalpha line feature of Cygnus X-1in the spectra of four simultaneous hard intermediate state observations madewith the X-ray Multiple Mirror mission (XMM-Newton), the Rossi X-ray TimingExplorer (RXTE), and the International Gamma-Ray Astrophysics Laboratory(INTEGRAL). The high quality of the XMM-Newton data taken in the ModifiedTiming Mode of the EPIC-pn camera provides a great opportunity to investigatethe broadened Fe Kalpha reflection line at 6.4keV with a very high signal tonoise ratio. The 4-500keV energy range is used to constrain the underlyingcontinuum and the reflection at higher energies. We first investigate the databy applying a phenomenological model that consists of the sum of anexponentially cutoff power law and relativistically smeared reflection.Additionally, we apply a more physical approach and model the irradiation ofthe accretion disk directly from the lamp post geometry. All four observationsshow consistent values for the black hole parameters with a spin of $a\sim0.9$, in agreement with recent measurements from reflection and disk continuumfitting. The inclination is found to be $i\sim30^\circ$, consistent with theorbital inclination and different from inclination measurements made during thesoft state, which show a higher inclination. We speculate that the differencebetween the inclination measurements is due to changes in the inner region ofthe accretion disk.

Revealing the broad iron Kalpha line in Cygnus X-1 through simultaneous XMM-Newton, RXTE, and INTEGRAL observations