Measuring the HI content of individual galaxies out to the epoch of reionization with [CII]

Abstract

The HI gas content is a key ingredient in galaxy evolution, the study of which has been limited to moderate cosmological distances for individual galaxies due to the weakness of the hyperfine HI 21-cm transition. Here we present a new approach that allows us to infer the HI gas mass $M_{\mathrm{HI}}$ of individual galaxies up to $z\approx 6$, based on a direct measurement of the [CII]-to-HI conversion factor in star-forming galaxies at $z\gtrsim 2$ using $\gamma$-ray burst afterglows. By compiling recent [CII]-158 $\mu$m emission line measurements we quantify the evolution of the HI content in galaxies through cosmic time. We find that the HI mass starts to exceed the stellar mass $M_{\star }$ at $z\gtrsim 1$, and increases as a function of redshift. The HI fraction of the total baryonic mass increases from around $20\%$ at $z=0$ to about $60\%$ at $z\sim 6$. We further uncover a universal relation between the HI gas fraction $M_{\mathrm{HI}}/M_{\star }$ and the gas-phase metallicity, which seems to hold from $z\approx 6$ to $z=0$. The majority of galaxies at $z>2$ are observed to have HI depletion times, $t_{\mathrm{dep},\mathrm{HI}}=M_{\mathrm{HI}}/\mathrm{SFR}$, less than $\approx 2$ Gyr, substantially shorter than for $z\sim 0$ galaxies. Finally, we use the [CII]-to-HI conversion factor to determine the cosmic mass density of HI in galaxies, ${\rho }_{\mathrm{HI}}$, at three distinct epochs: $z\approx 0$, $z\approx 2$, and $z\sim 4-6$. These measurements are consistent with previous estimates based on 21-cm HI observations in the local Universe and with damped Lyman-$\alpha$ absorbers (DLAs) at $z\gtrsim 2$, suggesting an overall decrease by a factor of $\approx 5$ in ${\rho }_{\mathrm{HI}}(z)$ from the end of the reionization epoch to the present.

Accepted for publication in ApJ

References in corpus (51)

• Cosmic Star Formation History
• The Supernova -- Gamma-Ray Burst Connection
• A Highly Consistent Framework for the Evolution of the Star-Forming "Main Sequence" from z~0-6
• xCOLD GASS: the complete IRAM-30m legacy survey of molecular gas for galaxy evolution studies
• The Evolution of the Star-forming Interstellar Medium across Cosmic Time
• The Mass-Metallicity and the Fundamental Metallicity Relation revisited on a fully Te-based abundance scale for galaxies
• On the (Non)Evolution of HI Disks over Cosmic Time
• The Cosmic Baryon and Metal Cycles
• The MOSDEF Survey: The Evolution of the Mass-Metallicity Relation from $z=0$ to $z\sim 3.3$
• The ALPINE-ALMA [CII] Survey: data processing, catalogs, and statistical source properties
• The Herschel Dwarf Galaxy Survey: I. Properties of the low-metallicity ISM from PACS spectroscopy
• The ALPINE-ALMA [CII] Survey: The nature, luminosity function and star formation history of dusty galaxies up to z~6
• Tracing the total molecular gas in galaxies: [CII] and the CO-dark gas
• The Neutral Hydrogen Cosmological Mass Density at z=5
• The HI content of star-forming galaxies at z = 0.24
• The ALPINE-ALMA [CII] Survey: Multi-Wavelength Ancillary Data and Basic Physical Measurements
• The ALPINE-ALMA [CII] Survey: Size of Individual Star-Forming Galaxies at z=4-6 and their Extended Halo Structure
• Star formation rate and dynamical mass of 10^8 solar mass black hole host galaxies at redshift 6
• The Evolution of the Baryons Associated with Galaxies Averaged over Cosmic Time and Space
• The line-of-sight towards GRB 030429 at z = 2.66: Probing the matter at stellar, galactic and intergalactic scales
• A Herschel [CII] Galactic plane survey III: [CII] as a tracer of star formation
• ALMA spectroscopic survey in the Hubble Ultra Deep Field: CO luminosity functions and the evolution of the cosmic density of molecular gas
• The ALPINE-ALMA [CII] survey: Molecular gas budget in the Early Universe as traced by [CII]
• The Origins of [CII] Emission in Local Star-forming Galaxies
• The Herschel Dwarf Galaxy Survey: II. Physical conditions, origin of [CII] emission, and porosity of the multiphase low-metallicity ISM
• The ALMA Spectroscopic Survey in the HUDF: Multi-band constraints on line luminosity functions and the cosmic density of molecular gas
• The Keck+Magellan Survey for Lyman Limit Absorption I: The Frequency Distribution of Super Lyman Limit Systems
• Turbulent Gas in Lensed Planck-selected Starbursts at redshifts 1-3.5
• ALMA [CII] detection of a redshift 7 lensed galaxy behind RXJ1347.1-1145
• Are LGRBs biased tracers of star formation? Clues from the host galaxies of the $Swift$/BAT6 complete sample of bright LGRBs III: Stellar masses, star formation rates and metallicities at $z>1$
• HI 21-centimetre emission from an ensemble of galaxies at an average redshift of one
• A kiloparsec view of a typical star-forming galaxy when the Universe was ~1 Gyr old. Part I. Outflow, halo, and interstellar medium properties
• Dust temperature in ALMA $\hbox{[C $\scriptstyle\rm II $]}$-detected high-$z$ galaxies
• Unveiling the Secrets of Metallicity and Massive Star Formation Using DLAs along Gamma-ray Bursts
• HI-MaNGA: Tracing the physics of the neutral and ionized ISM with the second data release
• CO emission in distant galaxies on and above the main sequence
• The Mass-Metallicity Relation at z=8: Direct-Method Metallicity Constraints and Near-Future Prospects
• The role of atomic hydrogen in regulating the scatter of the mass-metallicity relation
• A High Signal-to-Noise Ratio Composite Spectrum of Gamma-ray Burst Afterglows
• A study of the circum-galactic medium at z ~ 0.6 using DLA-galaxies
• [CII] 158 Micron Emission from z~4 HI Absorption-Selected Galaxies
• Giant Metrewave Radio Telescope Detection of HI 21 cm Emission from Star-forming Galaxies at $z\approx 1.3$
• The Local [CII] 158 um Emission Line Luminosity Function
• Probing the Physical Conditions of Atomic Gas at High Redshift
• The ALPINE-ALMA [C II] Survey: [C II]158micron Emission Line Luminosity Functions at $z\sim 4-6$
• Direct measurement of the [CI] luminosity to molecular gas mass conversion factor in high-redshift star-forming galaxies
• The evolution of neutral hydrogen over the past 11 Gyr via HI 21 cm absorption
• Characterizing the Multi-Phase Origin of [CII] Emission in M101 and NGC 6946 with Velocity Resolved Spectroscopy
• An Ultraviolet Survey of Low-Redshift Partial Lyman-Limit Systems with the HST Cosmic Origins Spectrograph
• Diagnosing the interstellar medium of galaxies with far-infrared emission lines I. The [C II] 158 microns line at z~0
• Redshift Evolution of the H2/HI Mass Ratio In Galaxies