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arXiv · 1209.1484

The Molecular Gas Content of z = 3 Lyman Break Galaxies; Evidence of a non Evolving Gas Fraction in Main Sequence Galaxies at z > 2

G. E. Magdis·E. Daddi·M. Sargent·D. Elbaz·R. Gobat·H. Dannerbauer·Q. Tan·C. Feruglio·D. Rigopoulou·V. Charmandaris·M. Dickinson·N. Reddy·H. Aussel
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Abstract

We present observations of the CO[3-2] emission towards two massive and infrared luminous Lyman Break Galaxies at z = 3.21 and z = 2.92, using the IRAM Plateau de Bure Interferometer, placing first constraints on the molecular gas masses (Mgas) of non-lensed LBGs. Their overall properties are consistent with those of typical (Main-Sequence) galaxies at their redshifts, with specific star formation rates ~1.6 and ~2.2 Gyr^(-1), despite their large infrared luminosities L_IR ~2-3 x 10^12 Lsun derived from Herschel. With one plausible CO detection (spurious detection probability of 10^(-3)) and one upper limit, we investigate the evolution of the molecular gas-to-stellar mass ratio (Mgas/M*) with redshift. Our data suggest that the steep evolution of Mgas/M* of normal galaxies up to z~2 is followed by a flattening at higher redshifts, providing supporting evidence for the existence of a plateau in the evolution of the specific star formation rate at z > 2.5.

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G. E. Magdis, E. Daddi, M. Sargent, D. Elbaz, R. Gobat, H. Dannerbauer, Q. Tan, C. Feruglio, D. Rigopoulou, V. Charmandaris, M. Dickinson, N. Reddy, H. Aussel. 2012-09-10. The Molecular Gas Content of z = 3 Lyman Break Galaxies; Evidence of a non Evolving Gas Fraction in Main Sequence Galaxies at z > 2. https://doi.org/10.1088/2041-8205%2F758%2F1%2Fl9

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