Do quasars form from primordial black holes?

Abstract We explore the consequences of a novel but increasingly well-supported hypothesis that supermassive black holes may have formed from primordial black holes (PBH) formed prior to, and rapidly growing in, the radiation-dominated universe. We show that this hypothesis and fuelling by accretion of dwarf galaxies, made up of predominantly subsolar mass PBH and accompanying gas, can predict the luminosity of quasars and their distribution in luminosity. With reasonable values of the parameters introduced, these predictions are borne out by observations. The model predicts density evolution in accordance with observations. If the same galaxy interaction rate creates quasars and radio galaxies, whose primordial black hole nuclei seem somewhat less massive, their relative number densities reflect relative lifetimes in these states.