Role of shocked accretion flows in regulating the QPO of galactic black hole candidates

Abstract

Using a generalized non-spherical, multi-transonic accretion flow model, we analytically calculate the normalized QPO frequency ${\bar {\bf ν}}_{qpo}$ of galactic black hole candidates in terms of dynamical flow variables and self-consistently study the dependence of ${\bar {\bf ν}}_{qpo}$ on such variables. Our results are in fairly close agreement with the observed QPO frequencies of GRS 1915+105. We find that ${\bar {\bf ν}}_{qpo}$ is quite sensitive to various parameters describing the black hole accretion flow containing dissipative and non-dissipative shock waves. Thus the QPO phenomena is, {\it indeed}, regulated by `shocked' black hole accretion, and, for the first time, we establish a definitive connection between the QPO frequency and the properties of advective BH accretion flows. This information may provide the explanation of some important observations of galactic micro quasars.