Diffuse hard X-ray emission in the galactic bulge

The bulge X-ray emission has been systematically studied with the ASCA and RXTE satellites. After removing the contribution from point sources, the presence of diffuse bulge X-ray emission consisting three distinct emission components, two thermal (cooler and hotter) and one non-thermal, has been established. The temperatures of the thermal components are essentially constant (0.6 keV and 3 keV) all over the bulge region, and surface brightness distributions of the hotter and non-thermal components are strongly correlated with each other. From the estimated scale of the hard X-ray bulge, total X-ray luminosity of the bulge emission is estimated to be similar to 10(38) erg s(-1), which is almost comparable to that of the well-known GRXE.