Formation of non-steady outflows and QPOs around black hole

Abstract

We study the time dependent properties of sub-Keplerian vis- cous accretion flow around the black holes. We find that rotating matter feels centrifugal barrier on the way towards the black holes and eventually, shock transition is triggered allowing a part of the post-shock matter to eject out as bipolar outflow. This outflowing matters are supposed to be the precursor of relativistic jets. As viscosity is increased, shock becomes un- steady and start to oscillate when viscosity reached its critical value. This causes the inner part of the disk unsteady resulting periodic ejection of mat- ter from the post-shock region. Also, the same hot and dense post-shock matter emits high energy radiation which modulates quasi-periodically. The power density spectra confirms this features as most of the power is concentrated at a narrow frequency range — a characteristics (i.e. Quasi- Periodic Oscillation) commonly seen in several outbursting black hole candidates.