Abstract

In this work, we have summarized (i) common methods to probe the central part of AGN, with a particular emphasis on key parameters such as mass of Super-Massive Black Holes (SMBHs) and Eddington ratios based on reverberation scaling relation and (ii) the caveat involved in method based on pure gas dynamics, such as role of non-gravitational radiation pressure. This is highlighted based on the recent evidence of very high velocity (up to 0.15c) associated absorber close to central region which probably are accelerated due to radiation driven winds.