Zavala, J.A. and Yun, M.S. and Aretxaga, I. and Hughes, D.H. and Wilson, G.W. and Geach, J.E. and Egami, E. and Gurwell, M.A. and Wilner, D.J. and Smail, I. and Blain, A.W. and Chapman, S.C. and Coppin, K.E.K. and Dessauges-Zavadsky, M. and Edge, A.C. and Montaña, A. and Nakajima, K. and Rawle, T.D. and Sánchez-Argüelles, D. and Swinbank, A.M. and Webb, T.M.A. and Zeballos, M. (2015) 'Early Science with the large millimeter telescope : observations of dust continuum and CO emission lines of cluster-lensed submillimetre galaxies at z=2.0-4.7.', Monthly notices of the Royal Astronomical Society., 452 (2). pp. 1140-1151.
We present Early Science observations with the Large Millimeter Telescope, AzTEC 1.1 mm continuum images and wide bandwidth spectra (73–111 GHz) acquired with the Redshift Search Receiver, towards four bright lensed submillimetre galaxies identified through the Herschel Lensing Survey-snapshot and the Submillimetre Common-User Bolometer Array-2 Cluster Snapshot Survey. This pilot project studies the star formation history and the physical properties of the molecular gas and dust content of the highest redshift galaxies identified through the benefits of gravitational magnification. We robustly detect dust continuum emission for the full sample and CO emission lines for three of the targets. We find that one source shows spectroscopic multiplicity and is a blend of three galaxies at different redshifts (z = 2.040, 3.252, and 4.680), reminiscent of previous high-resolution imaging follow-up of unlensed submillimetre galaxies, but with a completely different search method, that confirm recent theoretical predictions of physically unassociated blended galaxies. Identifying the detected lines as 12CO (Jup = 2–5) we derive spectroscopic redshifts, molecular gas masses, and dust masses from the continuum emission. The mean H2 gas mass of the full sample is (2.0 ± 0.2) × 1011 M⊙/μ, and the mean dust mass is (2.0 ± 0.2) × 109 M⊙/μ, where μ ≈ 2–5 is the expected lens amplification. Using these independent estimations we infer a gas-to-dust ratio of δGDR ≈ 55–75, in agreement with other measurements of submillimetre galaxies. Our magnified high-luminosity galaxies fall on the same locus as other high-redshift submillimetre galaxies, extending the L′CO–LFIR correlation observed for local luminous and ultraluminous infrared galaxies to higher far-infrared and CO luminosities.
|Keywords:||Galaxies: evolution, Galaxies: high-redshift, Galaxies: ISM, Cosmology: observations, Submillimetre: galaxies|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1093/mnras/stv1351|
|Publisher statement:||This article has been published in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Date accepted:||No date available|
|Date deposited:||04 November 2015|
|Date of first online publication:||September 2015|
|Date first made open access:||No date available|
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