The origin of Keplerian megamaser disks

Mark Wardle*, Farhad Yusef-Zadeh

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Several examples of 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 black hole mass and that such disks are naturally formed as molecular clouds pass through the galactic nucleus and temporarily engulf the central supermassive black hole. For initial cloud column densities below about 1023.5 cm-2 the disk is non-self gravitating, but 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.

Original languageEnglish (US)
Title of host publicationCosmic Masers - from OH to H0
EditorsRoy S. Booth, Elizabeth M. L. Humphreys, Wouter H.T. Vlemmings
Number of pages2
StatePublished - Jul 2012

Publication series

NameProceedings of the International Astronomical Union
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221


  • Galaxy: center
  • accretion
  • accretion disks
  • galaxies: Seyfert
  • masers

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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