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Title: 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 H{sub 2}O masers. For initial cloud column densities {approx}< 10{sup 23.5} cm{sup -2} the disk is non-self-gravitating, consistent with the ordered kinematics of the edge-on megamaser disks; for higher cloud columnsmore » the disk would fragment and produce a compact stellar disk similar to that observed around Sgr A* at the galactic center.« less

Authors:
 [1];  [2]
  1. Astronomy, Astrophysics and Astrophotonics Research Centre and Department of Physics and Astronomy, Macquarie University, Sydney, NSW 2109 (Australia)
  2. Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States)
Publication Date:
OSTI Identifier:
22047834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 750; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ANGULAR MOMENTUM; ASTRONOMY; ASTROPHYSICS; BLACK HOLES; CORRELATIONS; EFFICIENCY; GALAXY NUCLEI; GHZ RANGE; IRRADIATION; MASERS; MASS; SEYFERT GALAXIES; STARS; WATER; X RADIATION

Citation Formats

Wardle, Mark, and Yusef-Zadeh, Farhad, E-mail: mark.wardle@mq.edu.au, E-mail: zadeh@northwestern.edu. A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI. United States: N. p., 2012. Web. doi:10.1088/2041-8205/750/2/L38.
Wardle, Mark, & Yusef-Zadeh, Farhad, E-mail: mark.wardle@mq.edu.au, E-mail: zadeh@northwestern.edu. A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI. United States. doi:10.1088/2041-8205/750/2/L38.
Wardle, Mark, and Yusef-Zadeh, Farhad, E-mail: mark.wardle@mq.edu.au, E-mail: zadeh@northwestern.edu. 2012. "A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI". United States. doi:10.1088/2041-8205/750/2/L38.
@article{osti_22047834,
title = {A SCALING RELATION BETWEEN MEGAMASER DISK RADIUS AND BLACK HOLE MASS IN ACTIVE GALACTIC NUCLEI},
author = {Wardle, Mark and Yusef-Zadeh, Farhad, E-mail: mark.wardle@mq.edu.au, E-mail: zadeh@northwestern.edu},
abstractNote = {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 H{sub 2}O masers. For initial cloud column densities {approx}< 10{sup 23.5} cm{sup -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 center.},
doi = {10.1088/2041-8205/750/2/L38},
journal = {Astrophysical Journal Letters},
number = 2,
volume = 750,
place = {United States},
year = 2012,
month = 5
}
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