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Water Vapor in nearby Infrared Galaxies as Probed by Herschel

Yang, Chentao and Gao, Yu and Omont, A. and Liu, Daizhong and Isaak, K. G. and Downes, D. and van der Werf, P. P. and Lu, Nanyao (2013) Water Vapor in nearby Infrared Galaxies as Probed by Herschel. Astrophysical Journal Letters, 771 (2). Art. No. L24. ISSN 2041-8205.

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We report the first systematic study of the submillimeter water vapor rotational emission lines in infrared (IR) galaxies based on the Fourier Transform Spectrometer (FTS) data of Herschel SPIRE. Among the 176 galaxies with publicly available FTS data, 45 have at least one H_(2)O emission line detected. The H_(2)O line luminosities range from ~1 × 10^5 L_☉ to ~5 × 10^7 L_☉ while the total IR luminosities (L_IR) have a similar spread (~1-300 × 10^10 L_☉). In addition, emission lines of H_(2)O^+ and H^(18)_(2)O are also detected. H_(2)O is found, for most galaxies, to be the strongest molecular emitter after CO in FTS spectra. The luminosity of the five most important H_(2)O lines is near-linearly correlated with L_IR, regardless of whether or not strong active galactic nucleus signature is present. However, the luminosity of H_(2)O(2_11-2_02) and H_(2)O(2_20-2_11) appears to increase slightly faster than linear with L_IR. Although the slope turns out to be slightly steeper when z ~ 2-4 ULIRGs are included, the correlation is still closely linear. We find that L_H_(2)O/L_IR decreases with increasing f_25/f_60, but see no dependence on f_60/f_100, possibly indicating that very warm dust contributes little to the excitation of the submillimeter H_(2)O lines. The average spectral line energy distribution (SLED) of the entire sample is consistent with individual SLEDs and the IR pumping plus collisional excitation model, showing that the strongest lines are H_(2)O(2_02-1_11) and H_(2)O(3_21-3_12).

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
van der Werf, P. P.0000-0001-5434-5942
Lu, Nanyao0000-0002-8948-1044
Additional Information:© 2013 The American Astronomical Society. Received 2013 April 19; accepted 2013 May 27; published 2013 June 21. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. This research is based on the data from HSA and is partially supported by the NSF of China (No. 11173059). Facility: Herschel
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
National Natural Science Foundation of China11173059
Subject Keywords:galaxies: ISM; galaxies: starburst; infrared: ISM; ISM: molecules
Issue or Number:2
Record Number:CaltechAUTHORS:20130812-092216868
Persistent URL:
Official Citation:Water Vapor in nearby Infrared Galaxies as Probed by Herschel Chentao Yang (杨辰涛) et al. 2013 ApJ 771 L24
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39863
Deposited By: Jason Perez
Deposited On:12 Aug 2013 20:42
Last Modified:03 Oct 2019 05:11

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