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arXiv · 0802.1168

INTEGRAL observations of Her X-1

D. Klochkov·R. Staubert·K. Postnov·N. Shakura·A. Santangelo·S. Tsygankov·A. Lutovinov·I. Kreykenbohm·J. Wilms
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Abstract

Aims: We investigate the X-ray spectral and timing properties of the accreting X-ray pulsar Her X-1 observed with the INTEGRAL satellite in July-August 2005. Methods: The data analyzed in this work cover a substantial part of one main-on state of the source. The short-time scale pulse period development is measured. X-ray pulse profiles for different energy ranges and time intervals are constructed. Pulse-averaged and pulse-phase resolved broad band X-ray spectra are studied. Spectral changes during X-ray dips are explored. Results: The X-ray pulse profiles are found to change significantly during the period of observations. For the first time a strong spinup is measured within one 35 d cycle. Spectral characteristics observed during the X-ray dips are consistent with their interpretaion as due to partial covering as has been reported by several authors. The fundamental cyclotron absorption line is firmly observed in both pulse-averaged and pulse-phase resolved X-ray spectra. The energy, width, and the depth of the line are found to vary significantly with pulse phase.

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D. Klochkov, R. Staubert, K. Postnov, N. Shakura, A. Santangelo, S. Tsygankov, A. Lutovinov, I. Kreykenbohm, J. Wilms. 2008-02-08. INTEGRAL observations of Her X-1. https://doi.org/10.1051/0004-6361:20078953

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