A study of low mass X ray binaries

Abstract

In this work, we have investigated the spectral and temporal properties of thebrightest X-ray source (GX5-1) in the bulge of our Galaxy, using the data obtainedfrom the LAC instrument onboard the Ginga satellite. We have found that neithersingle-component spectral model (blackbody, thermal bremsstrahlung or power law)is adequate to fit the X-ray spectrum of GX5-1. The best fit is reached by using a.two-component model including a power law with exponential cut-off (PLEC) anda blackbody (BB). We have found positive evidence for the presence of a scatteringcloud surrounding the neutron star, with a Thomson optical depth of '` 5. The PLECcomponent is attributed to Comptonized emission in the scattering cloud while theBB component originates from an emission region in the inner accretion disk. Incontrast to some previous observations the source has been found to show only a,normal branch (NB) in its colour-colour diagram, but no horizontal branch (HB).We have found that the source shows no periodic intensity variations but a qua.siperiodicbehaviour, interpreted by some models in terms of the fluctuations in theoptical depth of the Comptonized medium.