ALMA shows that gas reservoirs of star-forming disks over the past 3 billion years are not predominantly molecular

Abstract

Cold hydrogen gas is the raw fuel for star formation in galaxies, and its partition into atomic and molecular phases is a key quantity for galaxy evolution. In this Letter, we combine Atacama Large Millimeter/submillimeter Array and Arecibo single-dish observations to estimate the molecular-to-atomic hydrogen mass ratio for massive star-forming galaxies at $z\sim$ 0.2 extracted from the HIGHz survey, i.e., some of the most massive gas-rich systems currently known. We show that the balance between atomic and molecular hydrogen in these galaxies is similar to that of local main-sequence disks, implying that atomic hydrogen has been dominating the cold gas mass budget of star-forming galaxies for at least the past three billion years. In addition, despite harboring gas reservoirs that are more typical of objects at the cosmic noon, HIGHz galaxies host regular rotating disks with low gas velocity dispersions suggesting that high total gas fractions do not necessarily drive high turbulence in the interstellar medium.

arXiv comment8 pages, 3 figures, 1 table. Accepted for publication in ApJ Letters. Minor changes to match published version

References in corpus (31)

• Galactic Stellar and Substellar Initial Mass Function
• The SINS survey: SINFONI Integral Field Spectroscopy of z ~ 2 Star-forming Galaxies
• PHIBSS: molecular gas content and scaling relations in z~1-3 normal star forming galaxies
• The Star-formation Mass Sequence out to z=2.5
• The Molecular Interstellar Medium in Ultraluminous Infrared Galaxies
• The SINS survey of z~2 galaxy kinematics: properties of the giant star forming clumps
• Combined CO & Dust Scaling Relations of Depletion Time and Molecular Gas Fractions with Cosmic Time, Specific Star Formation Rate and Stellar Mass
• The size evolution of galaxies since z~3: combining SDSS, GEMS and FIRES
• COLD GASS, an IRAM legacy survey of molecular gas in massive galaxies: I. Relations between H2, HI, stellar content and structural properties
• The GALEX Arecibo SDSS Survey. I. Gas Fraction Scaling Relations of Massive Galaxies and First Data Release
• ESI, a new Keck Observatory echellette spectrograph and imager
• The ISM in distant star-forming galaxies: Turbulent pressure, fragmentation and cloud scaling relations in a dense gas disk at z=2.3
• Cosmic evolution of the atomic and molecular gas content of galaxies
• Evolution of the atomic and molecular gas content of galaxies
• Cold gas properties of the Herschel Reference Survey. II. Molecular and total gas scaling relations
• Evidence for strong dynamical evolution in disk galaxies through the last 11 Gyr. GHASP VIII: A local reference sample of rotating disk galaxies for high redshift studies
• Cold gas properties of the Herschel Reference Survey. III. Molecular gas stripping in cluster galaxies
• The angular momentum distribution and baryon content of star forming galaxies at z~1-3
• Deriving a multivariate CO-to-H${}_2$ conversion function using the [CII]/CO(1-0) ratio and its application to molecular gas scaling relations
• The Dawes Review 1: Kinematic studies of star-forming galaxies across cosmic time
• KMOS^3D: Dynamical constraints on the mass budget in early star-forming disks
• Highest Redshift Image of Neutral Hydrogen in Emission: A CHILES Detection of a Starbursting Galaxy at z=0.376
• The Cosmic Decline in the H2/HI-Ratio in Galaxies
• PHIBSS: molecular gas, extinction, star formation and kinematics in the z=1.5 star forming galaxy EGS13011166
• HI and CO Velocity Dispersions in Nearby Galaxies
• HIGHz: A Survey of the Most HI-Massive Galaxies at z~0.2
• A Pilot Survey of HI in Field Galaxies at Redshift z~0.2
• The selective effect of environment on the atomic and molecular gas-to-dust ratio of nearby galaxies in the Herschel Reference Survey
• The Photometric and Kinematic Structure of Face-On Disk Galaxies. I. Sample Definition, H-alpha Integral Field Spectroscopy, and HI Line-Widths
• The radial variation of HI velocity dispersions in dwarfs and spirals
• Early Science with the Large Millimeter Telescope: COOL BUDHIES I - a pilot study of molecular and atomic gas at z~0.2

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