Broad band X-ray properties of GRO J1948+32/KS 1947+300

Abstract

We present here results obtained from three BeppoSAX observations of the transient X-ray pulsar GRO J1948+32 carried out during the declining phase of its 2000 November 2001 June outburst. Timing analysis of the data clearly shows a 18.7 s pulsation in the X-ray light curves in 0.1 100 keV energy band. The pulse profile of GRO 1948+32 is characterized by a broad peak with a sharp rise followed by a narrow dip. The dip in the pulse profile shows very strong energy dependence. Phase-averaged spectroscopy obtained with three of the BeppoSAX instruments shows that the 0.1 100 keV energy spectrum is described by a Comptonized component, a weak blackbody component (˜7% of the total emission) for soft X-rays, a narrow and weak iron emission line at 6.7 keV and low column density of material in the line of sight. The results obtained from the analysis are discussed in this paper.