A Fundamental Relation between Supermassive Black Holes and Their Host Galaxies

TLDR

Recent estimates of black hole masses by Magorrian et al. provide a baseline for studying their relation to host galaxies.

Abstract

The masses of supermassive black holes correlate almost perfectly with the velocity dispersions of their host bulges, Mbh ∝ σα, where α = 4.8 ± 0.5. The relation is much tighter than the relation between Mbh and bulge luminosity, with a scatter no larger than expected on the basis of measurement error alone. Black hole masses recently estimated by Magorrian et al. lie systematically above the Mbh-σ relation defined by more accurate mass estimates, some by as much as 2 orders of magnitude. The tightness of the Mbh-σ relation implies a strong link between black hole formation and the properties of the stellar bulge.