18 research outputs found
Green Bank Telescope Zpectrometer CO(1-0) Observations of the Strongly Lensed Submillimeter Galaxies from the Herschel ATLAS
The Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS) has
uncovered a population of strongly-lensed submillimeter galaxies (SMGs). The
Zpectrometer instrument on the Green Bank Telescope (GBT) was used to measure
the redshifts and constrain the masses of the cold molecular gas reservoirs for
two candidate high-redshift lensed sources. We derive CO(1-0) redshifts of
z=3.042+/-0.001 and z=2.625+/-0.001, and measure molecular gas masses of
(1--3)x10^{10}Msun, corrected for lens amplification and assuming a conversion
factor of alhpa=0.8 Msun(K km/s pc^2)^{-1}. We find typical L(IR)/L'(CO) ratios
of 120+/-40 and 140+/-50 Lsun (K km/s pc^2)^{-1}, which are consistent with
those found for local ULIRGs and other high-redshift SMGs. From analysis of
published data, we find no evidence for enhanced L(IR)/L'(CO(1-0)) ratios for
the SMG population in comparison to local ULIRGs. The GBT results highlight the
power of using the CO lines to derive blind redshifts, which is challenging for
the SMG population at optical wavelengths given their high obscuration.Comment: v1 Submitted to ApJL, 2010 Sept. 11; v2 Accepted by ApJL, 2010 Nov.
19; 15 pages including tables and figure