Understanding Galactic Black Hole Candidate GRS 1915+105

Abstract

We interpret observed features of the black hole candidate GRS1915+105 in the light of the advective flow paradigm. The light curve of this black hole is seen to be of four classes, Soft, Hard, Semi-Soft and Intermediate. Each class can display more than one type of light curve making altogether twelve or more types of light curves. In each type, the mode of accretion may be one or more of three types: which we identify as HW (hard state with winds), CC (Compton cooling) and EA (enhanced accretion) respectively. Apart from these three states there are two more fundamental states in a black hole accretion which are soft and hard states. We also find that winds and outflows could soften spectra in hard states and the enhanced accretion could harden the soft states. These are observed in the spectra of GRS 1915+105. Generally, we find that advective flow paradigm can satisfactorily explain all the features of the enigmatic black hole GRS 1915+105.