INTEGRAL observations of Her X-1
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.
Cite
@article{arxiv.0802.1168,
title = {INTEGRAL observations of Her X-1},
author = {D. Klochkov and R. Staubert and K. Postnov and N. Shakura and A. Santangelo and S. Tsygankov and A. Lutovinov and I. Kreykenbohm and J. Wilms},
journal= {arXiv preprint arXiv:0802.1168},
year = {2009}
}
Comments
9 pages, 10 figures, accepted for publication in A&A on 29/01/2008