X-ray spectroscopy of the high mass X-ray binary pulsar Centaurus X-3 over its orbit
Sachindra Naik1 and Biswajit Paul2
1Physical Research Laboratory, Ahmedabad
2Raman Research Institute, Bangalore
E-mail: snaik@prl.res.in

Abstract. Dipping activity in the X-ray intensity in binary systems is believed to be caused by the obscuration of X-rays from the compact object by structures located in the outer regions of the accretion disk. As dips are very rarely seen in the High Mass X-ray Binaries (HMXB) which is rather common in case low mass X-ray binaries, it is interesting to investigate the properties of the pulsar in HMXB systems showing dips. Here, we present a detailed and comprehensive spectral analysis of the of Suzaku observation of Centaurus X-3 covering the eclipse, out-of-eclipse, and dips in the light curve. The broadband energy spectra of the pulsar, during the eclipse, out-of-eclipse, and dips are found to be well described by a model consisting of a partial covering power-law with high energy cut-off and three Gaussian functions for 6.4 keV, 6.7 keV, and 6.9 keV iron emission lines. The dip in the X-ray light curve can be explained by the presence of an additional absorption component with high column density and covering fraction the values of which are not very significant during the rest of the orbital phases. The parameters of the three iron emission lines are also significantly different compared to those during the rest of the observation. The flux variations of the three iron line components are used to investigate the emission regions. The details of the results will be presented.