HI Absorption in the Gigamaser Galaxy TXS 2226-184 and the Relation between HI Absorption and Water Emission

Abstract

We report on the discovery of HI in absorption toward the gigamaser galaxy TXS2226-184 using the VLA. The absorption appears to consist of two components -- one with a width of 125 km/s, and one broader (420 km/s), both toward the compact radio source in the nucleus of the galaxy. Based on these large velocity widths we suggest that the HI absorption is produced in the central parsecs of the galaxy, on a similar scale to that which gives rise to the water maser emission. This brings to eight the number of galaxies known to exhibit both water masers and HI absorption. We explore the relationship between these two phenomena, and present a physically motivated (but unfruitful) search for water maser emission in five radio galaxies known to exhibit strong HI absorption.

arXiv comment19 pages including 5 figures, LaTeX, Accepted to ApJ

References in corpus (7)

• A Survey for H${}_2$O Megamasers in Active Galactic Nuclei -- II. A Comparison of Detected and Undetected Galaxies
• Neutral Hydrogen (21 cm) Absorption in Seyfert Galaxies: Evidence for Free-free Absorption and Sub-kiloparsec Gaseous Disks
• Obscuration of the Parsec Scale Jets in the Compact Symmetric Object 1946+708
• HI Absorption Toward the Nucleus of the Radio Galaxy PKS 2322-123 in A 2597
• Evidence for a Circumnuclear Disk in 1946+708
• Atomic and Molecular Gas in the Starburst Galaxy NGC4945
• HST and VLA Observations of the H2O Gigamaser Galaxy TXS2226-184

Cited by in corpus (13)

• Overview on spectral line source finding and visualisation
• The interstellar and circumnuclear medium of active nuclei traced by HI 21-cm absorption
• A search for HI absorption in nearby radio galaxies using HIPASS
• A Green Bank Telescope Search for Water Masers in Nearby Active Galactic Nuclei
• HI 21-cm absorption and unified schemes of active galactic nuclei
• A comparative study of intervening and associated HI 21-cm absorption profiles in redshifted galaxies
• Radio properties of H2O maser host galaxies
• Disks, Tori, and Cocoons: Emission and Absorption Diagnostics of AGN Environments
• A general relativistic estimation of the black hole mass-to-distance ratio at the core of TXS 2226-184
• Spectral characteristics of water megamaser galaxies II: ESO 103-G035, TXS 2226-184, and IC 1481
• VLBI observations of the H2O gigamaser in TXS2226-184
• Exploring the Nucleus of the Gigamaser Galaxy TXS 2226-184
• 21cm Absorption by Compact Hydrogen Disks Around Black Holes in Radio-Loud Nuclei of Galaxies