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Dynamical Structure of the Molecular Interstellar Medium in an Extremely Bright, Multiply Lensed z sime 3 Submillimeter Galaxy Discovered with Herschel

Riechers, DA; Cooray, A; Omont, A; Neri, R; Harris, AI; Baker, AJ; Cox, P; ... Wright, G; + view all (2011) Dynamical Structure of the Molecular Interstellar Medium in an Extremely Bright, Multiply Lensed z sime 3 Submillimeter Galaxy Discovered with Herschel. The Astrophysical Journal Letters , 733 (1) , Article L12. 10.1088/2041-8205/733/1/L12. Green open access

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Abstract

We report the detection of CO(J = 5 → 4), CO(J = 3 → 2), and CO(J = 1 → 0) emission in the strongly lensed, Herschel/SPIRE-selected submillimeter galaxy (SMG) HERMES J105751.1+573027 at z = 2.9574 ± 0.0001, using the Plateau de Bure Interferometer, the Combined Array for Research in Millimeter-wave Astronomy, and the Green Bank Telescope. The observations spatially resolve the molecular gas into four lensed images with a maximum separation of ~9'' and reveal the internal gas dynamics in this system. We derive lensing-corrected CO line luminosities of L'CO(1-0) = (4.17 ± 0.41), L'CO(3-2) = (3.96 ± 0.20), and L'CO(5-4) = (3.45 ± 0.20) × 1010 (μL/10.9)–1 K km s–1 pc2, corresponding to luminosity ratios of r 31 = 0.95 ± 0.10, r 53 = 0.87 ± 0.06, and r 51 = 0.83 ± 0.09. This suggests a total molecular gas mass of M gas = 3.3×1010 (αCO/0.8) (μL/10.9)–1 M ☉. The gas mass, gas mass fraction, gas depletion timescale, star formation efficiency, and specific star formation rate are typical for an SMG. The velocity structure of the gas reservoir suggests that the brightest two lensed images are dynamically resolved projections of the same dust-obscured region in the galaxy that are kinematically offset from the unresolved fainter images. The resolved kinematics appear consistent with the complex velocity structure observed in major, "wet" (i.e., gas-rich) mergers. Major mergers are commonly observed in SMGs and are likely to be responsible for fueling their intense starbursts at high gas consumption rates. This study demonstrates the level of detail to which galaxies in the early universe can be studied by utilizing the increase in effective spatial resolution and sensitivity provided by gravitational lensing.

Type: Article
Title: Dynamical Structure of the Molecular Interstellar Medium in an Extremely Bright, Multiply Lensed z sime 3 Submillimeter Galaxy Discovered with Herschel
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/2041-8205/733/1/L12
Publisher version: http://dx.doi.org/10.1088/2041-8205/733/1/L12
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Cosmology: observations, galaxies: active, galaxies: formation, galaxies: high-redshift, galaxies: starburst, radio lines: galaxies, PROBE WMAP OBSERVATIONS, GREEN-BANK-TELESCOPE, STAR-FORMATION, HIGH-REDSHIFT, ULTRALUMINOUS GALAXIES, MAJOR MERGERS, GAS, CO, Z=2.3, HCN
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Space and Climate Physics
URI: https://discovery.ucl.ac.uk/id/eprint/1330278
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