ON THE (NON)EVOLUTION OF H i GAS IN GALAXIES OVER COSMIC TIME

By X. Prochaska, A. Wolfe. 2008

260 citations recorded by the source corpus.

We present new results on the frequency distribution of projected H i column densities f(NH i, X), total comoving covering fraction, and integrated mass densities ρH i of high-redshift, H i galactic gas from a survey of damped Lyα systems (DLAs) in the Sloan Digital Sky Survey, Data Release 5. For the full sample spanning z = 2.2–5 (738 DLAs), f(NH i, X) is well fitted by a double power law with a break column density Nd = 1021.55±0.04 cm-2 and low/high-end exponents α = −2.00 ± 0.05, − 6.4+1.1−1.6. The shape of f(NH i, X) is invariant during this redshift interval and also follows the projected surface density distribution of present-day H i disks as inferred from 21 cm observations. We conclude that H i gas has been distributed in a self-similar fashion for the past 12 Gyr. The normalization of f(NH i, X), in contrast, decreases by a factor of 2 during the ≈2 Gyr interval from z = 4–2.2 with coincident decreases in both the total covering fraction and ρH i. At z ≈ 2, these quantities match the present-day values suggesting no evolution during the past ≈10 Gyr. We argue that the evolution at early times is driven by “violent” processes that removes gas from nearly half the galaxies at z ≈ 3 establishing the antecedents of current early-type galaxies. The perceived constancy of ρH i, meanwhile, implies that H i gas is a necessary but insufficient precondition for star formation and that the global star formation rate is driven by the accretion and condensation of fresh gas from the intergalactic medium.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/2c004e6277b8f8b6303f10b28bbc39ec6ce9bc18

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

Citations in the corpus

METALLICITY EVOLUTION OF DAMPED Lyα SYSTEMS OUT TO z ∼ 5 (2012, methodology): “Studies using DLA identifications from SDSS atz> 4 (Prochaska & Wolfe 2009) therefore need to apply a correction for the increased false positive rate before determining the column density distribution function, theotal covering fraction, and the integrated mass density of HI gas.”
Metallicity evolution, metallicity gradients, and gas fractions at z ~ 3.4 (2013, background): “Even more interesting, Prochaska & Wolfe (2009) have shown that the HI content in galaxies does not evolve in the redshift range 0 z 2.5, while it does evolve at higher redshifts.”
Physical Processes in the Interstellar Medium (2014, background): “This holds despite the continuous transformation of gas into stars, and it suggests that Hi is continuously replenished (Hopkins et al. 2008; Prochaska and Wolfe 2009).”
Neutral hydrogen in galaxy haloes at the peak of the cosmic star formation history (2014, background): “Inflows of gas from the intergalactic medium (IGM) are required to sustain the star formation rates that are measured across cosmic time (e.g., Prochaska & Wolfe 2009; Bauermeister et al. 2010).”
The neutral hydrogen content of galaxies in cosmological hydrodynamic simulations (2013, methodology): “Because galactic H i reservoirs are thought to represent a transient phase of baryons (Prochaska & Wolfe 2009) as they pass from the diffuse intergalactic medium (e.g. Davé et al. 2010) to higher density molecular gas, which eventually converts into stars, it is essential that models for cosmic H…”
H i intensity mapping: a single dish approach (2012, background): “Both observational (Prochaska & Wolfe 2009) and theoretical arguments (Duffy et al. 2011) appear to suggest that there is no more than a factor of 2 change in density of neutral hydrogen over the range of redshifts relevant to intensity mapping.”
A DEFINITIVE SURVEY FOR LYMAN LIMIT SYSTEMS AT z ∼ 3.5 WITH THE SLOAN DIGITAL SKY SURVEY (2009, methodology): “We also attempt to separate the contributions to ℓτ≥2(z) from SLLSa ℓSLLS(z), DLAs ℓDLA(z), and attribute the remainder to the LLSs with 1017.5 ≤ NHI < 10 19 cm−2, ℓLLS(z).”
The rising star formation histories of distant galaxies and implications for gas accretion with time (2010, methodology): “In order for the galaxies to maintain their high levels of star formation, it follows that they must receive cold gas from the intergalactic medium (IGM) to replenish their supplies of fresh gas to fuel the continued star formation (e.g., Erb 2008; Prochaska & Wolfe 2009).”
The most metal-poor damped Lyα systems: insights into chemical evolution in the very metal-poor regime★ (2011, methodology): “We derive an H i column density of log[N(H i)/cm−2] = 20.50 ± 0.08, which is consistent with estimates derived from the SDSS spectrum (log[N(H i)/cm−2] = 20.45; Prochaska & Wolfe 2009), as well as that derived by Penprase et al. (2010) (log[N(H i)/cm−2] = 20.40 ± 0.25).”
21CMMC: an MCMC analysis tool enabling astrophysical parameter studies of the cosmic 21 cm signal (2015, background): “Physically, this maximum horizon is taken to correspond to the mean free path of ionizing photons within ionized regions, Rmfp (e.g. O’Meara et al. 2007; Prochaska & Wolfe 2009; Songaila & Cowie 2010; McQuinn et al. 2011).”
Evolution of the cosmological mass density of neutral gas from Sloan Digital Sky Survey II - Data Release 7 (2009, methodology): “…of DLAs is a semi-automatic data mining of thousands of quasar spectra from the Sloan Digital Sky Survey (Prochaska & Herbert-Fort 2004; Prochaska et al. 2005; Prochaska & Wolfe 2009) revealing more than 700 new DLAs thus increasing by one order of magnitude the number of known DLAs atz > 2.2.”
An updated analytic model for attenuation by the intergalactic medium (2014, background): “…of the absorbers’ statistics, especially the discovery of almost no evolution of the DLA encounter probability per unit ‘absorption length’ (Prochaska & Wolfe 2009) and the new measurements of the meanfree-path of the Lyman limit photons (Prochaska et al. 2009; O’Meara et al. 2013;…”
MEASUREMENT OF 21 cm BRIGHTNESS FLUCTUATIONS AT z ∼ 0.8 IN CROSS-CORRELATION (2012, methodology): “Measurements with Sloan Digital Sky Survey (Prochaska and Wolfe 2009) suggest that beforez = 2, ΩHI may have already reached∼ 0.4 × 10−3.”
RADIATIVE TRANSFER IN A CLUMPY UNIVERSE. IV. NEW SYNTHESIS MODELS OF THE COSMIC UV/X-RAY BACKGROUND (2011, background): “With a power-law exponent β = 2 down to a break column of NHI = 10 21.55 cm−2 (Prochaska & Wolfe 2009), and with an incidence per unit redshift ∝ (1 + z)1.27 (Rao et al. 2006), the parameters for the DLAs becomes (A, β, γ) = (8.7× 1018, 2, 1.27).”
Inhomogeneous recombinations during cosmic reionization (2014, methodology): “In Figure 1 we compare the resulting CDDF with observational constraints at a mean redshift of 3.7 (O’Meara et al. 2007; Prochaska & Wolfe 2009; Prochaska et al. 2009, 2010).”