Optical properties of the host galaxies of extragalactic nuclear H2O masers

Ingyin Zaw, Guangtun Zhu, Michael Blanton, Lincoln J. Greenhill

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


Although most nuclear 22GHz (=1.35 cm) H2O masers are in Seyfert 2 and LINER galaxies, only a small fraction of such galaxies host water masers. We systematically study the optical properties of the galaxies with and without nuclear H2O maser emission to better understand the relationship between H2O maser emission and properties of the central supermassive black hole and improve the detection rates in future surveys. To this end, we cross-matched the galaxies from H2O maser surveys, both detections and non-detections, with the Sloan Digital Sky Survey (SDSS) low-redshift galaxy sample. We find that maser detection rates are higher at higher optical luminosity (MB ), larger velocity dispersion (), and higher ion [O III] 5007 luminosity, with [O III] 5007 being the dominant factor, and that the isotropic maser luminosity is correlated with these variables. These correlations are natural if maser emission depends on the host SMBH mass and AGN activity. We also find that the detection rate is higher for galaxies with higher extinction. These results indicate that, by pre-selecting galaxies with high extinction-corrected [O III] 5007 flux, future maser surveys can increase detections efficiencies by a factor of ∼3 to ∼5.

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 pages5
StatePublished - Jul 2012

Publication series

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


  • galaxies: Seyfert
  • galaxies: active
  • galaxies: nuclei
  • masers
  • radio lines: galaxies

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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