1998/04/17 by C. Henkel, Henkel, C., Y. P. Wang +7
Physics and Astronomy · #Astrophysics and Cosmic Phenomena #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/9804176
A&A, in press, A&A Latex, 5 pages, also available at http://www.mpifr-bonn.mpg.de/mpivlb/falcke/publications.html#h2o
arxiv created 1998/04/17 · arxiv updated 2009/12/01
A systematic search for 22 GHz H2O megamaser emission is reported for 50 nearby (z < 0.15) FR I galaxies. No detection was obtained, implying that ultraluminous H2O masers (LH2O>103 Lsun) must be rare in early-type galaxies with FR I radio morphology. Despite higher radio core luminosities the detection rate for our sample is much lower than in similar surveys of late-type Seyfert galaxies. This puzzling difference between Seyferts and low-power radio galaxies could be explained in several ways: a) the maser emission is saturated and therefore independent of the radio core luminosity, b) the masers are unsaturated and the background continuum source is associated with the counter jet which is beamed away and relativistically dimmed in radio-galaxies, or c) the amount, kinematics, or the distribution of the molecular gas in the nuclei of Seyferts and radio galaxies is different. Further studies of maser properties may therefore hold a clue for morphological differences between active nuclei of Seyfert and early-type radio galaxies.