%0 Journal Article
%T Blind detections of CO J = 1--0 in 11 H-ATLAS galaxies at z = 2.1--3.5 with the GBT/Zpectrometer
%A A. I. Harris
%A A. J. Baker
%A D. T. Frayer
%A Ian Smail
%A A. M. Swinbank
%A D. A. Riechers
%A P. P. van der Werf
%A R. Auld
%A M. Baes
%A R. S. Bussmann
%A S. Buttiglione
%A A. Cava
%A D. L. Clements
%A A. Cooray
%A H. Dannerbauer
%A A. Dariush
%A G. DeZotti
%A L. Dunne
%A S. Dye
%A S. Eales
%A J. Fritz
%A J. Gonzalez-Nuevo
%A R. Hopwood
%A E. Ibar
%A R. J. Ivison
%A M. J. Jarvis
%A S. Maddox
%A M. Negrello
%A E. Rigby
%A D. J. B. Smith
%A P. Temi
%A J. Wardlow
%J Physics
%D 2012
%I arXiv
%R 10.1088/0004-637X/752/2/152
%X We report measurements of the carbon monoxide ground state rotational transition (12C16O J = 1--0) with the Zpectrometer ultra-wideband 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 100um. The CO detections confirm the existence of massive gas reservoirs within these luminous dusty star-forming galaxies (DSFGs). The CO redshift distribution of the 350um-selected galaxies is strikingly similar to the optical redshifts of 850um-selected submillimeter galaxies (SMGs) 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 difficult determine from 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 mu from spectroscopic data alone, yielding mu ~ 3--20. Corrected for magnification, most galaxy luminosities are consistent with an ultra-luminous infrared galaxy (ULIRG) classification, but three are candidate hyper-LIRGs with luminosities greater than 10^13 L_sun.
%U http://arxiv.org/abs/1204.4706v1