On the black hole mass - velocity dispersion relation for type-1 and type-2 AGN

TL;DR

This study investigates the black hole mass-velocity dispersion relation in active galactic nuclei using infrared spectroscopy, revealing that gas emission lines can serve as proxies for stellar velocity dispersions, especially in obscured AGN.

Contribution

The paper demonstrates that near-infrared high-resolution spectroscopy can effectively extend the black hole mass-velocity dispersion relation to high-luminosity and obscured AGN populations.

Findings

Infrared spectroscopy helps populate the high-luminosity end of the relation.

Mid-infrared high-ionization lines follow the same relation as stellar velocity dispersions.

Gas emission lines can be used to estimate black hole masses in obscured AGN.

Abstract

We present results from infrared spectroscopic projects that aim to test the relation between the mass of a black hole, M_BH, and the velocity dispersion of the stars in its host-galaxy bulge. We demonstrate that near-infrared, high-resolution spectroscopy assisted by adaptive optics is key in populating the high-luminosity end of the relation. We show that the velocity dispersions of mid-infrared, high-ionization lines originating from gas in the narrow-line region of the active galactic nucleus follow the same relation. This result provides a way of inferring M_BH estimates for the cosmologically significant population of obscured, type-2 AGN that can be applicable to data from spectrographs on the next generation infrared telescopes.