Coppin, K. E. K. and Swinbank, A. M. and Neri, R. and Cox, P. and Smail, Ian and Ellis, R. S. and Geach, J. E. and Siana, B. and Teplitz, H. and Dye, S. and Kneib, J.-P. and Edge, A. C. and Richard, J. (2007) A Detailed Study of Gas and Star Formation in a Highly Magnified Lyman Break Galaxy at z = 3.07. Astrophysical Journal, 665 (2). pp. 936-943. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20100205-090953449
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We report the detection of CO(3-2) emission from a bright, gravitationally lensed Lyman Break galaxy, LBG J213512.73-010143 (the "Cosmic Eye"), at z = 3.07, using the Plateau de Bure Interferometer. This is only the second detection of molecular gas emission from an LBG and yields an intrinsic molecular gas mass of (2.4 ± 0.4) × 10^9 M_⊙. The lens reconstruction of the UV morphology of the LBG indicates that it comprises two components separated by ~2 kpc. The CO emission is unresolved, θ ≾ 3", and appears to be centered on the intrinsically fainter (and also less highly magnified) of the two UV components. The width of the CO line indicates a dynamical mass of (8 ± 2) × 10^9csc^2i M_⊙ within the central 2 kpc. Employing mid-infrared observations from Spitzer, we infer a stellar mass of M_* ~ (6 ± 2) × 10^9 M_⊙ and a star formation rate of ~60 M_⊙ yr^(-1), indicating that the molecular gas will be consumed in ≾ 40 Myr. The gas fractions, star formation efficiencies, and line widths suggests that LBG J213512 is a high-redshift, gas-rich analog of a local luminous infrared galaxy. This galaxy has a similar gas-to-dynamical mass fraction as observed in the submillimeter-selected population, although the gas surface density and star formation efficiency is a factor of 3 times less, suggesting less vigorous activity. We discuss the uncertainties in our conclusions arising from adopting a CO-to-H_2 conversion factor appropriate for either the Milky Way or local luminous infrared galaxies. These observations demonstrate that current facilities, when aided by fortuitous gravitational magnification, can study "ordinary" galaxies at high redshift and so act as pathfinders for ALMA.
|Additional Information:||© 2007 The American Astronomical Society. Received 2007 April 4; accepted 2007 May 10. This work is based on observations carried out with the IRAM PdBI. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). This work also makes use of data obtained with Spitzer, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. We thank the Spitzer director, Tom Soifer, for the award of the Spitzer DDT. We thank Max Pettini, Alice Shapley, and Dave Alexander for useful discussions and help, and an anonymous referee for a constructive report. K. E. K. C., A. M. S., and J. E. G. acknowledge support from PPARC. I. R. S. acknowledges support from the Royal Society.|
|Subject Keywords:||cosmology : observations; galaxies : evolution; galaxies : formation; galaxies : individual; (LBG J213512.73-010143); galaxies : kinematics and dynamics; galaxies : starburst|
|Official Citation:||A Detailed Study of Gas and Star Formation in a Highly Magnified Lyman Break Galaxy at z = 3.07 K. E. K. Coppin, A. M. Swinbank, R. Neri, P. Cox, Ian Smail, R. S. Ellis, J. E. Geach, B. Siana, H. Teplitz, S. Dye, J.-P. Kneib, A. C. Edge, and J. Richard 2007 ApJ 665 936-943 doi: 10.1086/519789|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||09 Feb 2010 02:55|
|Last Modified:||26 Dec 2012 11:45|
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