Pulse profiles of binary X-ray pulsars in 20-200 keV band

Abstract

Hard X-ray observations of the binary X-ray pulsars were made using a balloon-borne large area scintillation counter telescope in the 20-200 keV band. Apart from many other galactic and extragalactic X-ray sources, three X-ray pulsars namely Her X-1, GS 1843+00 and 4U 1907+09 were tracked during two flights launched in March 1997 and Nov. 1998. The observations of the transient sources GS 1843+00 correspond to near intensity maximum in its burst phase. We discuss the morphology of the pulse profiles in terms of geometrical constraints and the X-ray emission mechanism.