The Quasar Mass-Luminosity Plane II: High Mass Turnoff Evolution and a Synchronization Puzzle

Understand

We use 62,185 quasars from the Sloan Digital Sky Survey DR5 sample and standard virial mass scaling laws based on the widths of H beta, Mg II, and C IV lines and adjacent continuum luminosities to explore the maximum mass of quasars as a function of redshift, which we find to be sharp and evolving.

• This evolution is in the sense that high-mass black holes cease their luminous accretion at higher redshift than lower-mass black holes.
• Further, turnoff for quasars at any given mass is more highly synchronized than would be expected given the dynamics of their host galaxies.
• We investigate potential signatures of the quasar turnoff mechanism, including a dearth of high-mass quasars at low Eddington ratio.