The Hydroxyl-Water Megamaser Connection. I. Water Emission Toward OH Megamaser Hosts

Abstract

Questions surround the connection of luminous extragalactic masers to galactic processes. The observation that water and hydroxyl megamasers rarely coexist in the same galaxy has given rise to a hypothesis that the two species appear in different phases of nuclear activity. The detection of simultaneous hydroxyl and water megamaser emission toward IC694 has called this hypothesis into question but, because many megamasers have not been surveyed for emission in the other molecule, it remains unclear whether IC694 occupies a narrow phase of galaxy evolution or whether the relationship between megamaser species and galactic processes is more complicated than previously believed. In this paper, we present results of a systematic search for 22 GHz water maser emission among OH megamaser hosts to identify additional objects hosting both megamaser. Our work roughly doubles the number of galaxies searched for emission in both molecules which host at least one confirmed maser. We confirm with high degree of confidence ($>8\sigma$) the detection of water emission toward IIZw96, firmly establishing it as the second object to co-host both water and hydroxyl megamasers after IC694. We find high luminosity, narrow features in the water feature in IIZw96. All dual megamaser candidates appear in merging galaxy systems suggestive that megamaser coexistance may signal a brief phase along the merger sequence. A statistical analysis of the results of our observations provide possible evidence for an exclusion of H${}_2$O kilomasers among OH megamaser hosts.

8 pages, 6 figures, accepted to ApJ

References in corpus (8)

• Toward a New Geometric Distance to the Active Galaxy NGC 4258. III. Final Results and the Hubble Constant
• Integral field spectroscopy of the Luminous Infrared Galaxy Arp299 (IC694+NGC3690)
• Discovery of Water Maser Emission in Five AGN and a Possible Correlation Between Water Maser and Nuclear 2-10 keV Luminosities
• New Compton-thick AGN in the circumnuclear water maser hosts UGC3 789 and NGC 6264
• Detection of a methanol megamaser in a major-merger galaxy
• A Dense Gas Trigger for OH Megamasers
• An embedded active nucleus in the OH megamaser galaxy IRAS16399-0937
• 22 GHz Water Maser Search in 37 Nearby Galaxies - Four New Water Megamasers in Seyfert 2 and OH Maser/Absorber Galaxies

Cited by in corpus (10)

• GOALS-JWST: Unveiling Dusty Compact Sources in the Merging Galaxy IIZw096
• First detection of the 448 GHz H2O transition in space
• Hubble distancing: Focusing on distance measurements in cosmology
• High Resolution Observations of Molecular Lines in Arp 220: Kinematics, Morphology, and Limits on the Applicability of the Ammonia Thermometer
• Discovery of Methanimine Megamasers Toward Compact Obscured Galaxy Nuclei
• Gemini IFU, VLA, and HST observation of the OH Megamaser Galaxy IRAS17526+3253
• Radio properties of the OH megamaser galaxy IIZw 096
• A Spectral Analysis of the Centimeter Regime of Nearby Galaxies: RRLs, Excited OH, and NH${}_3$
• FASHI: A search for extragalactic OH megamasers with FAST
• Extragalactic maser surveys