Measuring the low mass end of the Mbh - sigma relation

TL;DR

This paper demonstrates the feasibility of high-quality laser guide star adaptive optics observations of nearby galaxies for measuring black hole masses, even with limited spatial resolution, by combining high-resolution and large field data.

Contribution

It introduces a method for effective AO correction using nuclei guiding and open loop focus compensation, enabling black hole mass measurements with less stringent resolution requirements.

Findings

Achieved 40% flux correction within 0.2 arcsec

Showed lower limits on black hole mass can be set with sub-optimal resolution

Validated AO technique for black hole studies in nearby galaxies

Abstract

We show that high quality laser guide star (LGS) adaptive optics (AO) observations of nearby early-type galaxies are possible when the tip-tilt correction is done by guiding on nuclei while the focus compensation due to the changing distance to the sodium layer is made 'open loop'. We achieve corrections such that 40% of flux comes from R<0.2 arcsec. To measure a black hole mass (Mbh) one needs integral field observations of both high spatial resolution and large field of view. With these data it is possible to determine the lower limit to Mbh even if the spatial resolution of the observations are up to a few times larger than the sphere of influence of the black hole.