On the low detection efficiency of disk water megamasers in Seyfert 2 AGN

摘要

Disk megamasers are a unique tool to study active galactic nuclei (AGN)sub-pc environment, and precisely measure some of their fundamental parameters.While the majority of disk megamasers are hosted in heavily obscured (i.e.,Seyfert 2, Sy2) AGN, the converse is not true, and disk megamasers are veryrarely found even in obscured AGN. The very low detection rate of such systemsin Sy2 AGN could be due to the geometry of the maser beaming, which requires astrict edge-on condition. We explore some other fundamental factors which couldplay a role in a volume-limited survey of disk megamasers in Sy2 galaxies, mostimportantly the radio luminosity.