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Blind Detections of CO J = 1–0 in 11 H-ATLAS Galaxies at z = 2.1–3.5 with the GBT/Zpectrometer

Harris, A. I. and Riechers, D. A. (2012) Blind Detections of CO J = 1–0 in 11 H-ATLAS Galaxies at z = 2.1–3.5 with the GBT/Zpectrometer. Astrophysical Journal, 752 (2). Art. No. 152. ISSN 0004-637X. doi:10.1088/0004-637X/752/2/152.

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We report measurements of the carbon monoxide ground state rotational transition (^(12)C^(16)O J = 1-0) with the Zpectrometer ultrawideband spectrometer on the 100 m diameter Green Bank Telescope. The sample comprises 11 galaxies with redshifts between z = 2.1 and 3.5 from a total sample of 24 targets identified by Herschel-ATLAS photometric colors from the SPIRE instrument. Nine of the CO measurements are new redshift determinations, substantially adding to the number of detections of galaxies with rest-frame peak submillimeter emission near 100 μm. The CO detections confirm the existence of massive gas reservoirs within these luminous dusty star-forming galaxies (DSFGs). The CO redshift distribution of the 350 μm selected galaxies is strikingly similar to the optical redshifts of 850 μm-selected submillimeter galaxies in 2.1 ≤ z ≤ 3.5. Spectroscopic redshifts break a temperature-redshift degeneracy; optically thin dust models fit to the far-infrared photometry indicate characteristic dust temperatures near 34 K for most of the galaxies we detect in CO. Detections of two warmer galaxies, and statistically significant nondetections, hint at warmer or molecule-poor DSFGs with redshifts that are difficult to determine from Herschel-SPIRE photometric colors alone. Many of the galaxies identified by H-ATLAS photometry are expected to be amplified by foreground gravitational lenses. Analysis of CO linewidths and luminosities provides a method for finding approximate gravitational lens magnifications μ from spectroscopic data alone, yielding μ ~ 3-20. Corrected for magnification, most galaxy luminosities are consistent with an ultraluminous infrared galaxy classification, but three are candidate hyper-LIRGs with luminosities greater than 10^(13) L_☉.

Item Type:Article
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URLURL TypeDescription
Harris, A. I.0000-0001-6159-9174
Riechers, D. A.0000-0001-9585-1462
Additional Information:© 2012 American Astronomical Society. Received 2011 December 19; accepted 2012 April 19; published 2012 June 6. We thank L. Leeuw, M. Michalowski, and I. Valtchanov for their comments on aspects of this work. We acknowledge support from the National Science Foundation under grant numbers AST-0503946 to the University of Maryland and AST- 0708653 to Rutgers University. D.T.F. acknowledges support by NASA through an award issued by JPL/Caltech; D.R. acknowledges support from NASA through a Spitzer Space Telescope Grant; I.R.S. and A.M.S. acknowledge support from STFC; S.B. acknowledges financial contribution from the agreement ASIINAF I/009/10/0; J.G.N. acknowledges financial support from Spanish CSIC for a JAE-DOC fellowship and partial financial support from the Spanish Ministerio de Ciencia e Innovacion project AYA2010-21766-C03-01. Results here came from GBT programs 8C-09 (PI Smail), 9A-40 (PI Swinbank), 10C-29 (PI Frayer), and 11A-27 (PI Frayer). We thank the GBT staff for their support and contributions. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. The Herschel-ATLAS is a project with Herschel, which is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. The H-ATLAS Web site is Facilities: GBT, Herschel
Funding AgencyGrant Number
NASA Spitzer Space TelescopeUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)I/009/10/0
Ministerio de Ciencia e Innovación (MCINN)AYA2010-21766-C03-01
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Subject Keywords:galaxies: evolution; galaxies: high-redshift; galaxies: ISM; submillimeter: galaxies
Issue or Number:2
Record Number:CaltechAUTHORS:20120720-094616444
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Official Citation:Blind Detections of CO J = 1–0 in 11 H-ATLAS Galaxies at z = 2.1–3.5 with the GBT/Zpectrometer A. I. Harris et al. 2012 ApJ 752 152
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:32602
Deposited By: Jason Perez
Deposited On:20 Jul 2012 20:16
Last Modified:09 Nov 2021 21:28

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