Effects of Biases in Virial Mass Estimation on Cosmic Synchronization of Quasar Accretion

TL;DR

This study examines how potential systematic biases in virial mass estimates affect observed quasar properties, revealing that some key phenomena are robust while others depend heavily on mass calibration.

Contribution

It demonstrates that cosmic synchronization and accretion independence are unaffected by biases, but the sub-Eddington boundary's characteristics are highly sensitive to mass estimation methods.

Findings

Cosmic synchronization persists despite mass biases.

Sub-Eddington boundary's slope and position vary with mass calibration.

Alternative mass estimators introduce new complexities in quasar behavior.

Abstract

Recent work using virial mass estimates and the quasar mass-luminosity plane has yielded several new puzzles regarding quasar accretion, including a sub-Eddington boundary on most quasar accretion, near-independence of the accretion rate from properties of the host galaxy, and a cosmic synchronization of accretion among black holes of a common mass. We consider how these puzzles might change if virial mass estimation turns out to have a systematic bias. As examples, we consider two recent claims of mass-dependent biases in MgII masses. Under any such correction, the surprising cosmic synchronization of quasar accretion rates and independence from the host galaxy remain. The slope and location of the sub-Eddington boundary are very sensitive to biases in virial mass estimation, and various mass calibrations appear to favor different possible physical explanations for feedback between the central black hole and its environment. The alternative mass estimators considered do not simply remove puzzling quasar behavior, but rather replace it with new puzzles that may be more difficult to solve than those using current virial mass estimators and the Shen et al. (2008) catalog.