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A Water Maser and NH_3 Survey of GLIMPSE Extended Green Objects

Cyganowski, C. J. and Koda, J. and Rosolowsky, E. and Towers, S. and Donovan Meyer, J. and Egusa, F. and Momose, R. and Robitaille, T. P. (2013) A Water Maser and NH_3 Survey of GLIMPSE Extended Green Objects. Astrophysical Journal, 764 (1). Art. No. 61. ISSN 0004-637X.

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We present the results of a Nobeyama 45 m H_(2)O maser and NH_3 survey of all 94 northern GLIMPSE extended green objects (EGOs), a sample of massive young stellar objects (MYSOs) identified based on their extended 4.5 μm emission. We observed the NH3(1,1), (2,2), and (3,3) inversion lines, and detected emission toward 97%, 63%, and 46% of our sample, respectively (median rms ~ 50 mK). The H_(2)O maser detection rate is 68% (median rms ~ 0.11 Jy). The derived H_(2)O maser and clump-scale gas properties are consistent with the identification of EGOs as young MYSOs. To explore the degree of variation among EGOs, we analyze subsamples defined based on mid-infrared (MIR) properties or maser associations. H_(2)O masers and warm dense gas, as indicated by emission in the higher-excitation NH_3 transitions, are most frequently detected toward EGOs also associated with both Class I and II CH_(3)OH masers. Ninety-five percent (81%) of such EGOs are detected in H_(2)O (NH_(3)(3,3)), compared to only 33% (7%) of EGOs without either CH_(3)OH maser type. As populations, EGOs associated with Class I and/or II CH3OH masers have significantly higher NH_3 line widths, column densities, and kinetic temperatures than EGOs undetected in CH_(3)OH maser surveys. However, we find no evidence for statistically significant differences in H_(2)O maser properties (such as maser luminosity) among any EGO subsamples. Combining our data with the 1.1 mm continuum Bolocam Galactic Plane Survey, we find no correlation between isotropic H_(2)O maser luminosity and clump number density. H_(2)O maser luminosity is weakly correlated with clump (gas) temperature and clump mass.

Item Type:Article
Related URLs:
URLURL TypeDescription
Koda, J.0000-0002-8762-7863
Rosolowsky, E.0000-0002-5204-2259
Donovan Meyer, J.0000-0002-3106-7676
Robitaille, T. P.0000-0002-8642-1329
Additional Information:© 2013 American Astronomical Society. Received 2012 May 15; accepted 2012 October 12; published 2013 January 28. We thank the staff at the Nobeyama Radio Observatory for their support during our observing runs. This research has made use of NASA’s Astrophysics Data System Bibliographic Services and the SIMBAD database operated at CDS, Strasbourg, France. Support for this work was provided by NSF grant AST-0808119. C.J.C. was partially supported during this work by a National Science Foundation Graduate Research Fellowship, and is currently supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1003134. C.J.C. thanks M. Reid for helpful discussions about kinematic distances, and J. Brown, L. Chomiuk, and H. Kirk for IDL insight. E.R. is supported by a Discovery Grant from NSERC of Canada.
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
NSF Astronomy and Astrophysics Postdoctoral FellowshipAST-1003134
Natural Sciences and Engineering Research Council of Canada (NSERC)UNSPECIFIED
Subject Keywords:infrared: ISM; ISM: jets and outflows; ISM: molecules; masers; stars: formation
Issue or Number:1
Record Number:CaltechAUTHORS:20130308-101045357
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Official Citation:A Water Maser and NH3 Survey of GLIMPSE Extended Green Objects C. J. Cyganowski et al. 2013 ApJ 764 61
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:37412
Deposited By: Jason Perez
Deposited On:08 Mar 2013 21:53
Last Modified:09 Mar 2020 13:19

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