The Megamaser Cosmology Project. XII. VLBI Imaging of H$_{2}$O Maser Emission in Three Active Galaxies and the Effect of AGN Winds on Disk Dynamics

TL;DR

This study uses VLBI imaging to analyze water maser emissions in three active galaxies, revealing how AGN winds influence disk dynamics and black hole mass estimations, with implications for understanding AGN environments.

Contribution

First VLBI imaging of water masers in three active galaxies, demonstrating the impact of AGN winds on disk kinematics and black hole mass measurements.

Findings

IRAS 08452-0011 shows a Keplerian disk and a black hole of ~3.3x10^7 M_sun.

NGC 5728 and Mrk 1 exhibit complex gas kinematics, hindering black hole mass determination.

Disturbed maser environments are common, indicating significant AGN wind influence.

Abstract

We present VLBI images and kinematics of water maser emission in three active galaxies: NGC 5728, Mrk 1, and IRAS 08452-0011. IRAS 08452-0011 is a triple-peaked H2O megamaser, consistent with a Keplerian rotating disk, indicating a black hole mass of (3.3+/-0.2)x10^7 M_sun. NGC 5728 and Mrk 1 display double-peaked spectra and VLBI imaging reveal complicated gas kinematics, which do not allow for a robust determination of black hole mass. The two systems are either gas disks perturbed by AGN winds or part of outflows. We find that disturbed morphology and kinematics are a ubiquitous feature of all double-peaked maser systems, implying that these maser sources may reside in environments where AGN winds are prominent at ~1 pc scale and have significant impact on the masing gas. Such AGN tend to have black hole mass M_BH < 8x10^6 M_sun and Eddington ratios lambda_Edd >~ 0.1, while the triple-peaked megamasers show an opposite trend.