On the BH-galaxy relation of AGN and Narrow Line Seyfert 1 Galaxies

TL;DR

This paper reviews the relationship between black hole mass and host galaxy properties in active galactic nuclei, highlighting differences in Narrow Line Seyfert 1 galaxies and recent updates in the field.

Contribution

It provides an updated review of the black hole-galaxy relations, emphasizing the peculiarities of Narrow Line Seyfert 1 galaxies and recent observational findings.

Findings

NLS1 galaxies have lower BH/bulge mass ratios.

BH mass correlates with host galaxy luminosity similarly in active and inactive galaxies.

The BH/bulge ratio correlates with the velocity dispersion of broad line gas.

Abstract

Massive black holes (BHs) are detected in the centers of many nearby galaxies are linearly correlated with the luminosity of the host bulge (spheroid), the black hole mass being about 0.1% of the stellar mass. In active galaxies, the BH mass is best measured by the reverberation mapping (light echo) technique. We and others have shown that in AGNs the BH mass follows the same relation with the luminosity of the host galaxy as in ordinary (inactive) galaxies, with the exception of narrow line AGNs which apparently have significantly lower values of the BH/bulge mass (or BH/bulge luminosity) ratio. The BH/bulge ratio is also found to be strongly correlated with the velocity dispersion of the broad line-emitting gas in the active nucleus. However, in the BH-stellar velocity relation the difference between broad- and narrow-line AGNs (in particular NLS1s) seems to be less obvious. We review the subject adding recent updates and suggestions.