Large Scale Structure traced by Molecular Gas at High Redshift

Abstract

We present observations of redshifted CO(1-0) and CO(2-1) in a field containing an overdensity of Lyman break galaxies (LBGs) at z=5.12. Our Australia Telescope Compact Array observations were centered between two spectroscopically-confirmed z=5.12 galaxies. We place upper limits on the molecular gas masses in these two galaxies of M(H_2) <1.7 x 10^10 M_sun and <2.9 x 10^9 M_sun (2 sigma), comparable to their stellar masses. We detect an optically-faint line emitter situated between the two LBGs which we identify as warm molecular gas at z=5.1245 +/- 0.0001. This source, detected in the CO(2-1) transition but undetected in CO(1-0), has an integrated line flux of 0.106 +/- 0.012 Jy km/s, yielding an inferred gas mass M(H_2)=(1.9 +/- 0.2) x 10^10 M_sun. Molecular line emitters without detectable counterparts at optical and infrared wavelengths may be crucial tracers of structure and mass at high redshift.

4 pages, accepted for publication in ApJ Letters

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Cited by in corpus (10)

• Are z~5 QSOs found in the most massive high redshift over-densities?
• Detection of molecular gas in a distant submillimetre galaxy at z=4.76 with ATCA
• Spectroscopy of z~5 Lyman Break Galaxies in the ESO Remote Galaxy Survey
• Constraining the Molecular Gas in the Environs of a z~8 Gamma Ray Burst Host Galaxy
• Observational limits on the gas mass of a z=4.9 galaxy
• The first spectral line surveys searching for signals from the Dark Ages
• Limits on the Molecular Gas Content of z-5 LBGs
• Molecular gas and dust in the highly magnified z = 2.8 galaxy behind the Bullet Cluster
• Constraining the Thermal Dust Content of Lyman-Break Galaxies in an Overdense Field at z~5
• Limits on dust emission from z~5 LBGs and their local environments