The Discovery of Water Maser Emission from Eight Nearby Galaxies
Using the Green Bank Telescope, we conducted a 'snapshot' survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted of nearby ([image] km s[image]) and luminous galaxies, some with known nuclear activity but most not previously k...
Gespeichert in:
Veröffentlicht in: | The Astrophysical journal 2008-05, Vol.678 (1), p.96-101 |
---|---|
Hauptverfasser: | , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext bestellen |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Using the Green Bank Telescope, we conducted a 'snapshot' survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted of nearby ([image] km s[image]) and luminous galaxies, some with known nuclear activity but most not previously known to host AGNs. Our detections include both megamasers associated with AGNs and relatively low luminosity masers probably associated with star formation. The detection in UGC 3789 is particularly intriguing because the spectrum shows both systemic and high-velocity lines indicative of emission from an AGN accretion disk seen edge-on. Based on 6 months of monitoring, we detected accelerations among the systemic features ranging from 2 to 8 km s[image] yr[image], the larger values belonging to the most redshifted systemic components. High-velocity maser lines in UGC 3789 show no detectable drift over the same period. Although UGC 3789 was not known to be an AGN prior to this survey, the presence of a disk maser is strong evidence for nuclear activity, and an optical spectrum obtained later has confirmed it. With follow-up observations, it may be possible to measure a geometric distance to UGC 3789. |
---|---|
ISSN: | 0004-637X 1538-4357 |
DOI: | 10.1086/529538 |