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

TL;DR

This paper investigates why disk water megamasers are rarely detected in Seyfert 2 AGN, examining factors like geometry and radio luminosity that influence detection rates.

Contribution

It explores additional fundamental factors beyond geometry, such as radio luminosity, affecting the low detection efficiency of disk megamasers in Seyfert 2 AGN.

Findings

Detection rate is influenced by maser beaming geometry.

Radio luminosity may play a significant role in detection.

Other factors could contribute to the low detection efficiency.

Abstract

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 very rarely found even in obscured AGN. The very low detection rate of such systems in Sy2 AGN could be due to the geometry of the maser beaming, which requires a strict edge-on condition. We explore some other fundamental factors which could play a role in a volume-limited survey of disk megamasers in Sy2 galaxies, most importantly the radio luminosity.