Details

Autor(en) / Beteiligte

• Greene, Jenny E
• Peng, Chien Y
• Kim, Minjin
• Kuo, Cheng-Yu
• Braatz, James A
• Impellizzeri, C. M. Violette
• Condon, James J
• Lo, K. Y
• Henkel, Christian
• Reid, Mark J

Titel

Precise Black Hole Masses from Megamaser Disks: Black Hole-Bulge Relations at Low Mass

Ist Teil von

• The Astrophysical journal, 2010-09, Vol.721 (1), p.26-45

Ort / Verlag

Bristol: IOP Publishing

Erscheinungsjahr

2010

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• The black hole (BH)-bulge correlations have greatly influenced the last decade of efforts to understand galaxy evolution. Current knowledge of these correlations is limited predominantly to high BH masses (M{sub BH{approx}}>10{sup 8} M{sub sun}) that can be measured using direct stellar, gas, and maser kinematics. These objects, however, do not represent the demographics of more typical L < L* galaxies. This study transcends prior limitations to probe BHs that are an order of magnitude lower in mass, using BH mass measurements derived from the dynamics of H{sub 2}O megamasers in circumnuclear disks. The masers trace the Keplerian rotation of circumnuclear molecular disks starting at radii of a few tenths of a pc from the central BH. Modeling of the rotation curves, presented by Kuo et al., yields BH masses with exquisite precision. We present stellar velocity dispersion measurements for a sample of nine megamaser disk galaxies based on long-slit observations using the B and C spectrograph on the Dupont telescope and the Dual Imaging Spectrograph on the 3.5 m telescope at Apache Point. We also perform bulge-to-disk decomposition of a subset of five of these galaxies with Sloan Digital Sky Survey imaging. The maser galaxies as a group fall below the M{sub BH}-{sigma}{sub *} relation defined by elliptical galaxies. We show, now with very precise BH mass measurements, that the low-scatter power-law relation between M{sub BH} and {sigma}{sub *} seen in elliptical galaxies is not universal. The elliptical galaxy M{sub BH}-{sigma}{sub *} relation cannot be used to derive the BH mass function at low mass or the zero point for active BH masses. The processes (perhaps BH self-regulation or minor merging) that operate at higher mass have not effectively established an M{sub BH}-{sigma}{sub *} relation in this low-mass regime.