Abstract Details

Name: Rajiv kumar
Affiliation: Department of Astronomy, Xiamen University, China
Conference ID: ASI2017_1177
Title : Theoretical and Numerical Investigations of Accretion-Ejection Mechanism around Compact objects
Authors and Co-Authors : Dr. Indranil Chattopadhyay
Abstract Type : Thesis
Abstract Category : Thesis
Abstract : The goal of this thesis is to understand the black hole accretion process, outflows and jets, and predict its observational properties. In the study of accretion disc, the highly non-linear process involves a transport of angular momentum by turbulent viscosity process and dissipation in the disc by various dissipative process. The disc in a full general relativistic regime is a very hard to study analytically. So here firstly, we have study analytically hydrodynamic disc with using pseudo-Newtonian geometry around compact objects then using full general relativistic approach. Pseudo-Newtonian potential carrys essential properties of general relativity such as the location of marginally stable orbit, the location of marginally bound orbit and the location of photon orbit and their corresponding angular momentum values. So, this mimic the black hole geometry with general relativity. This Pseudo-potential is given by and also known as Paczyn´ski and Wiita (1980) potential. Our accretion solutions are stationary, axisymmetric without or with turbulent viscosity in the disc around non-rotating black holes. We have developed all type of possible accretion solutions in a self-consistent manner for non-dissipative or dissipative process in the disc. We have mainly focused on shock disc solutions and jets solutions by assuming jets flow geometry around black hole with their corresponding disc luminosities. The accretion solutions have also been studied with time dependent numerical simulation by us. We want to check how well our numerical simulations by state of the art simulation code, can reproduce our analytical solutions, and thereby acts as check of our predictions based on analytical result. This thesis mainly focused on two things, which are the origin of jets and the dynamics of the accretion discs. How does a collimated outflow arise from the hot accretion disc and spiraling into a central object ? Why do jets appear to turn “on” and “off” as the accretion disc changes spectral states ? So, it is mainly divided into two parts one explains the dissipative and non- dissipative accretion disc model and other focused on jet geometry and outflow mechanism. These two main parts are also further divided into two parts on the basis of fixed and variable adiabatic index (Γ) equation of states for the fluids and in final part, I have concluded my work.