Spectral Signature of Wind Generation From The Post-Shock Region in GRS1915+105 Accretion Disk

Abstract

Accretion and outflows are common in systems which include black holes. Especially important is the case of the well known micro-quasar GRS1915+105 in our own galaxy, where super-luminal outflows are detected. We present a few observation which are suggestive of an outflow which is generated very close to the black hole, within a few tens of Schwarzschild radii. In the presence of mass loss (e.g., an outflowing wind), the electron density of matter within the centrifugal pressure supported region (which generates hard X-rays) goes down and it is easier to cool these electrons by soft photons coming from the Keplerian disk. If, on the other hand, the post-shock region gains mass from outside, the spectra would be harder. These properties of spectral `softening' of the low state and `hardening' of the high state have been detected in several days of RXTE data of GRS1915+105 which we present here.