The Mass of Quasars

Understand

I review the current status of quasar black hole (BH) mass estimations.

• Spectroscopic methods have been developed to estimate BH mass in broad line quasars to an accuracy of ~0.5 dex.
• Despite their popularity, significant issues and confusion remain regarding these mass estimators.
• I provide an in-depth discussion on the merits and caveats of the single-epoch (SE) virial BH mass estimators, and a detailed derivation of the statistical biases of these SE mass estimates resulting from their errors.