SUPERMASSIVE BLACK HOLES IN THE HIERARCHICAL UNIVERSE: A GENERAL FRAMEWORK AND OBSERVATIONAL TESTS

Abstract

(Abridged) We present a simple framework for the growth and evolution of supermassive black holes (SMBHs) in the hierarchical structure formation paradigm. In our model, black hole accretion is triggered during major mergers (mass ratio>~0.3) between host dark matter halos. The successive evolution of quasar luminosities follows a universal light curve form: an initial exponential growth at constant Eddington ratio of order unity until it reaches the peak luminosity, followed by a power-law decay. Assuming that the peak luminosity correlates with the post-merger halo mass, we convolve the light curve with the triggering rate of quasar activity to predict the quasar luminosity function (LF). Our model reproduces the observed LF at 0.5 ~10^46 erg s^-1) to low luminosity AGNs (L_bol<~ 10^45 erg s^-1), in good agreement with observations.