Coevolution (Or Not) of Supermassive Black Holes and Host Galaxies: Black Hole Scaling Relations Are Not Biased by Selection Effects

TL;DR

This paper argues that selection effects do not bias the observed correlations between supermassive black hole masses and host galaxy properties, supporting the idea that black holes coevolve primarily with classical bulges and ellipticals.

Contribution

It provides a detailed discussion and evidence that selection biases do not affect the observed black hole-host galaxy scaling relations, reinforcing the coevolution hypothesis.

Findings

Black hole correlations are not biased by selection effects.

Strong correlations exist only with classical bulges and ellipticals.

Pseudobulges and disks show weaker, upper-envelope correlations.

Abstract

The oral version of this paper summarized Kormendy & Ho 2013, ARA&A, 51, 511. However, earlier speakers at this Symposium worried that selection effects bias the derivation of black hole scaling relations. I therefore added -- and this proceedings paper emphasizes -- a discussion of why we can be confident that selection effects do not bias the observed correlations between BH mass M_BH and the luminosity, stellar mass, and velocity dispersion of host ellipticals and classical bulges. These are the only galaxy components that show tight BH-host correlations. The scatter plots of M_BH with host properties for pseudobulges and disks are upper envelopes of scatter that does extend to lower BH masses. BH correlations are most consistent with a picture in which BHs coevolve only with classical bulges and ellipticals. Four physical regimes of coevolution (or not) are suggested by Kormendy & Ho 2013 and are summarized here.