High gas fraction in a CO-selected main-sequence galaxy at $z>3$

Abstract

We report NOrthern Extended Millimetre Array (NOEMA) observations of warm molecular gas traced by CO($5-4$) in a $z\sim 3.2$ gas-rich main-sequence galaxy (MS), initially serendipitously detected in CO($3-2$) emission in `blind' deep NOEMA observations. Our target shows a gas excitation consistent with that seen in $z\sim 1.5$ MS galaxies ($L_{\mathrm{CO}(5-4)}^{\prime }/L_{\mathrm{CO}(3-2)}^{\prime }=0.41\pm 0.14$), albeit toward the low end, as well as a similar star formation efficiency based on the CO($3-2$) line luminosity and the $L_{\mathrm{IR}}$. However, it shows a high molecular gas fraction ($f_{\mathrm{gas}}=0.9\pm 0.2$) as compared to $z\sim 1.5$ MS galaxies ($f_{\mathrm{gas}}\sim 0.4$), consistent with a cosmologically increasing gas fraction beyond $z\gtrsim 3$ and our current understanding of scaling relations between $z$, $f_{\mathrm{gas}}$, the stellar mass $M_{\ast }$, and the specific star formation rate sSFR. Our results are consistent with recent findings by the COLDz and ASPECS molecular line scan surveys and suggest that deep searches for CO emission are a powerful means to identify gas-rich, star-forming galaxies at high redshift.

10 pages, 4 figures, accepted to the Astrophysical Journal

References in corpus (27)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Infrared Emission from Interstellar Dust. IV. The Silicate-Graphite-PAH Model in the Post-Spitzer Era
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• 3D-HST WFC3-selected Photometric Catalogs in the Five CANDELS/3D-HST Fields: Photometry, Photometric Redshifts and Stellar Masses
• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• A Dust-Obscured Massive Maximum-Starburst Galaxy at a Redshift of 6.34
• xCOLD GASS: the complete IRAM-30m legacy survey of molecular gas for galaxy evolution studies
• COLD GASS, an IRAM Legacy Survey of Molecular Gas in Massive Galaxies: II. The non-universality of the Molecular Gas Depletion Timescale
• Evolution of the dust emission of massive galaxies up to z=4 and constraints on their dominant mode of star formation
• CO excitation of normal star forming galaxies out to z=1.5 as regulated by the properties of their interstellar medium
• The impact of interactions, bars, bulges, and AGN on star formation efficiency in local massive galaxies
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Survey Description
• Highly-excited CO emission in APM08279+5255 at z=3.9
• The far-infrared/radio correlation and radio spectral index of galaxies in the SFR-M* plane up to z 2
• CO(1-0) in z >/~ 4 Quasar Host Galaxies: No Evidence for Extended Molecular Gas Reservoirs
• ISM properties of a Massive Dusty Star-Forming Galaxy discovered at z ~ 7
• Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z~2-4 as probed by multi-J CO lines
• ALMA spectroscopic survey in the Hubble Ultra Deep Field: CO luminosity functions and the evolution of the cosmic density of molecular gas
• ALMA Spectroscopic Survey in the Hubble Ultra Deep Field: Molecular gas reservoirs in high-redshift galaxies
• The Cosmic Decline in the H2/HI-Ratio in Galaxies
• Gas Fraction and Depletion Time of Massive Star Forming Galaxies at z~3.2: No Change in Global Star Formation Process out to z>3
• Molecular gas content in strongly-lensed z~1.5-3 star-forming galaxies with low IR luminosities
• A Detailed Study of Gas and Star Formation in a Highly Magnified Lyman Break Galaxy at z=3.07
• ALMA Reveals Weak [NII] Emission in "Typical" Galaxies and Intense Starbursts at z=5-6
• Modelling CO emission from hydrodynamic simulations of nearby spirals, starbursting mergers, and high-redshift galaxies
• Dust and Gas in Star Forming Galaxies at z~3 - Extending Galaxy Uniformity to 11.5 Billion Years
• The infrared-radio correlation of spheroid- and disc-dominated star-forming galaxies to z $\sim$ 1.5 in the COSMOS field

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