A Scaling Relation Between Megamaser Disk Radius and Black Hole Mass in Active Galactic Nuclei

Abstract

Several thin, Keplerian, sub-parsec megamaser disks have been discovered in the nuclei of active galaxies and used to precisely determine the mass of their host black holes. We show that there is an empirical linear correlation between the disk radius and the black hole mass. We demonstrate that such disks are naturally formed by the partial capture of molecular clouds passing through the galactic nucleus and temporarily engulfing the central supermassive black hole. Imperfect cancellation of the angular momenta of the cloud material colliding after passing on opposite sides of the hole leads to the formation of a compact disk. The radial extent of the disk is determined by the efficiency of this process and the Bondi-Hoyle capture radius of the black hole, and naturally produces the empirical linear correlation of the radial extent of the maser distribution with black hole mass. The disk has sufficient column density to allow X-ray irradiation from the central source to generate physical and chemical conditions conducive to the formation of 22 GHz H2O masers. For initial cloud column densities less than ~10^{23.5} cm^-2 the disk is non-self gravitating, consistent with the ordered kinematics of the edge-on megamaser disks; for higher cloud columns the disk would fragment and produce a compact stellar disk similar to that observed around Sgr A* at the galactic centre.

Minor revisions. Fig 1. corrected. ApJ Letters, in press

References in corpus (10)

• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Simulations of star formation in a gaseous disc around sgr A* - a failed AGN
• Star Formation Around Super-Massive Black Holes
• On the Formation of Compact Stellar Disks Around Sgr A*
• Toward a New Distance to the Active Galaxy NGC 4258: II. Centripetal Accelerations and Investigation of Spiral Structure
• The Parsec-scale Accretion Disk in NGC 3393
• Evolution of Star Clusters near the Galactic Center: Fully Self-consistent N-body Simulations
• The torquing of circumnuclear accretion disks by stars and the evolution of massive black holes
• Accretion disk warping by resonant relaxation: The case of maser disk NGC4258
• In situ formation of the massive stars around SgrA*

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• Signatures of Young Star Formation Activity Within Two Parsecs of Sgr A*
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• Constraining dark matter by the 511 keV line
• Reviewing the GR Method for Estimating Black Hole Parameters of Megamaser Systems