Title:	Orbital phase spectroscopy of GX 301-2 with RXTE-PCA
Authors:	Mukherjee, U. Paul, Biswajit
Issue Date:	Nov-2004
Publisher:	EDP Sciences
Citation:	Astronomy and Astrophysics, 2004, Vol. 427, p567-573
Abstract:	We have investigated the orbital phase dependence of the X-ray spectrum of the High Mass X-ray Binary pulsar GX 301-2. Here we present the results from a spectral analysis of two sets of observations of GX 301-2 with the Rossi X-ray Timing Explorer (RXTE). Of particular interest are the variations of the absorption column density and the iron line flux along with other parameters of the spectral model with the orbital phase. We found that the X-ray spectrum can almost always be fitted with a partial covering absorption model. We have detected enhanced absorption near the periastron. However, the column density variation with orbital phase is not smooth, as is expected in a smooth stellar wind model. We discuss the results of the column density variation in the light of the two proposed models for GX 301-2, an equatorial disk emanating from the companion star Wray 977 and a gas stream following the neutron star. We also found that the iron Kα and Kβ line fluxes have peaks near the periastron and are well correlated with the continuum hard X-ray flux. The line equivalent width shows an interesting pattern with the column density, reasonably constant for low values of the column density and increasing rapidly beyond a certain value.
Description:	Open Access
URI:	http://hdl.handle.net/2289/4976
ISSN:	0004-6361
Alternative Location:	http://adsabs.harvard.edu/abs/2004A%26A...427..567M http://arxiv.org/abs/astro-ph/0409056 http://dx.doi.org/10.1051/0004-6361:20034407
Copyright:	2004 EDP Sciences
Appears in Collections:	Research Papers (A&A)

Items in RRI Digital Repository are protected by copyright, with all rights reserved, unless otherwise indicated.