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Observational evidence for a changing tilt of the accretion disk with respect to the orbital plane in Her X-1 over its 35 day cycle

D. Klochkov·N. Shakura·K. Postnov·R. Staubert·J. Wilms·N. Ketsaris
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Abstract

Analysis and interpretation of the Her X-1 X-ray light curve obtained with the ASM onbord RXTE over the period 1996 February to 2004 September is presented. We report that the features found previously in the averaged X-ray lightcurve are confirmed by the new RXTE/ASM data. In particular, anomalous dips and post-eclipse recoveries in two successive orbits in the short-on state are found to be prominent and stable details of the light curve. We argue that a change of the tilt of the accretion disk over the 35-day period is necessary to account for these features and show that our numerical model can explain such a behavior of the disk and reproduce the observed details of the light curve.

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D. Klochkov, N. Shakura, K. Postnov, R. Staubert, J. Wilms, N. Ketsaris. 2007-11-12. Observational evidence for a changing tilt of the accretion disk with respect to the orbital plane in Her X-1 over its 35 day cycle. https://arxiv.org/abs/astro-ph/0609276

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