Low-luminosity Active Galaxies and their Central Black Holes
Loading...
Date
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
Central black hole masses for 118 spiral galaxies representing morphological stages S0/a through Sc and taken from the large spectroscopic survey of Ho, Filippenko & Sargent (1997) are derived using 2MASS Ks data. Black hole (BH) masses are found using a calibrated black-hole - Ks bulge luminosity relation, while bulge luminosities are measured using GALFIT, a two-dimensional bulge/disk decomposition routine.
The BH masses are correlated against a variety of nuclear and host-galaxy properties. Nuclear properties such as line width and line ratios show a very high degree of correlation with BH mass. The excellent correlation with line-width supports the view that the emission-line gas is in virial equilibrium with either the BH or bulge potential. The very good emission-line ratio correlations may indicate a change in ionizing continuum shape with BH mass in the sense that more massive BHs generate harder spectra.
Apart from the inclination-corrected rotational velocity, no excellent correlations are found between BH mass and host-galaxy properties.
Significant differences are found between the distributions of BH masses in early-, mid- and later-type spiral galaxies in the sense that early-type galaxies have preferentially larger central BHs. The line-width distributions show a marked difference among the subsamples in the sense that earlier-type galaxies have larger line widths. There are also clear differences in line ratios between subsamples likely related to the level of ionization in the gas. Finally, a Ks-band Simien & de Vaucouleurs diagram shows excellent agreement with the original B-band relation.
Accepted by A.J
Accepted by A.J