Evidence for Short $\sim 1$ Myr Lifetimes from the He II Proximity Zones of $z\sim 4$ Quasars

Ilya S. Khrykin, Joseph F. Hennawi, Gabor Worseck

The duration of quasar accretion episodes is a key quantity for distinguishing between models for the formation and growth of supermassive black holes, the evolution of quasars, an…