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The Gas Consumption History to z ~ 4
Cosmology and Nongalactic Astrophysics · Submitted 21 Sep 2009
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim We show that to be consistent with observational constraints, star formation on cosmic timescales must be fueled by intergalactic ionized gas, which may come from either accretion of gas through cold (but ionized) flows or from ionized gas associated with accretion of dark matter halos.
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Using the observations of the star formation rate and HI densities to z ~ 4, with measurements of the Molecular Gas Depletion Rate (MGDR) and local density of H_2 at z = 0, we derive the history of the gas consumption by star formation to z ~ 4. We find that closed-box models in which H_2 is not replenished by HI require improbably large increases in rho(H_2) and a decrease in the MGDR with lookback time that is inconsistent with observations. Allowing the H_2 used in star formation to be replenished by HI does not alleviate the problem because observations show that there is very little evolution of rho(HI) from z = 0 to z = 4. We show that to be consistent with observational constraints, star formation on cosmic timescales must be fueled by intergalactic ionized gas, which may come from either accretion of gas through cold (but ionized) flows or from ionized gas associated with accretion of dark matter halos. We constrain the rate at which the extraglactic ionized gas must be converted into HI and ultimately into H_2. The ionized gas inflow rate roughly traces the SFRD: about 1 - 2 x 10^8 M_sun Gyr^-1 Mpc^-3 from z ~ 1 - 4, decreasing by about an order of magnitude from z=1 to z=0 with details depending largely on MGDR(t). All models considered require the volume averaged density of rho(H_2) to increase by a factor of 1.5 - 10 to z ~ 1.5 over the currently measured value. Because the molecular gas must reside in galaxies, it implies that galaxies at high z must, on average, be more molecule rich than they are at the present epoch, which is consistent with observations. These quantitative results, derived solely from observations, agree well with cosmological simulations.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | Using the observations of the star formation rate and HI densities to z ~ 4, with measurements of the Molecular Gas Depletion Rate (MGDR) and local density of H_2 at z = 0, we derive the history of the gas consumption by star formation to z ~ 4. | method 0.51 | 0.91 | 0.08 | asserted 0.99 |
| s1 | We find that closed-box models in which H_2 is not replenished by HI require improbably large increases in rho(H_2) and a decrease in the MGDR with lookback time that is inconsistent with observations. | result 0.96 | 0.91 | 0.07 | asserted 1.00 |
| s2 | Allowing the H_2 used in star formation to be replenished by HI does not alleviate the problem because observations show that there is very little evolution of rho(HI) from z = 0 to z = 4. | result 0.91 | 0.52 | 0.05 | asserted 1.00 |
| s3 | We show that to be consistent with observational constraints, star formation on cosmic timescales must be fueled by intergalactic ionized gas, which may come from either accretion of gas through cold (but ionized) flows or from ionized gas associated with accretion of dark matter halos. | result 0.55 | 0.88 | 0.82 | asserted 0.83 |
| s4 | We constrain the rate at which the extraglactic ionized gas must be converted into HI and ultimately into H_2. | contribution 0.64 | 0.93 | 0.07 | asserted 0.99 |
| s5 | The ionized gas inflow rate roughly traces the SFRD: about 1 - 2 x 10^8 M_sun Gyr^-1 Mpc^-3 from z ~ 1 - 4, decreasing by about an order of magnitude from z=1 to z=0 with details depending largely on MGDR(t). | result 1.00 | 0.90 | 0.11 | asserted 0.96 |
| s6 | All models considered require the volume averaged density of rho(H_2) to increase by a factor of 1.5 - 10 to z ~ 1.5 over the currently measured value. | result 1.00 | 0.90 | 0.10 | asserted 0.99 |
| s7 | Because the molecular gas must reside in galaxies, it implies that galaxies at high z must, on average, be more molecule rich than they are at the present epoch, which is consistent with observations. | interpretation 0.99 | 0.62 | 0.09 | hedged possibility 0.67 |
| s8 | These quantitative results, derived solely from observations, agree well with cosmological simulations. | interpretation 0.51 | 0.76 | 0.08 | asserted 0.98 |
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The paper
Original abstract
Using the observations of the star formation rate and HI densities to z ~ 4, with measurements of the Molecular Gas Depletion Rate (MGDR) and local density of H_2 at z = 0, we derive the history of the gas consumption by star formation to z ~ 4. We find that closed-box models in which H_2 is not replenished by HI require improbably large increases in rho(H_2) and a decrease in the MGDR with lookback time that is inconsistent with observations. Allowing the H_2 used in star formation to be replenished by HI does not alleviate the problem because observations show that there is very little evolution of rho(HI) from z = 0 to z = 4. We show that to be consistent with observational constraints, star formation on cosmic timescales must be fueled by intergalactic ionized gas, which may come from either accretion of gas through cold (but ionized) flows or from ionized gas associated with accretion of dark matter halos. We constrain the rate at which the extraglactic ionized gas must be converted into HI and ultimately into H_2. The ionized gas inflow rate roughly traces the SFRD: about 1 - 2 x 10^8 M_sun Gyr^-1 Mpc^-3 from z ~ 1 - 4, decreasing by about an order of magnitude from z=1 to z=0 with details depending largely on MGDR(t). All models considered require the volume averaged density of rho(H_2) to increase by a factor of 1.5 - 10 to z ~ 1.5 over the currently measured value. Because the molecular gas must reside in galaxies, it implies that galaxies at high z must, on average, be more molecule rich than they are at the present epoch, which is consistent with observations. These quantitative results, derived solely from observations, agree well with cosmological simulations.
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How the literature uses it
2 arXiv papers cite this in 3 sentences
What it cites · 7 sentences without a confident label
Uses data or values from 3 papers
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We begin with the dark matter accretion rate from [ref] and [ref] , which quantified the mass accretion histories of all dark matter halos with masses above $∼10^10$ M$_⊙$ in the two Millennium simulations of a $Λ$CDM universe [ref] .
Mass Accretion Rates and Histories of Dark Matter Haloes · Comparing $d/dt$ to Dark Matter Accretion Rate · 0.98
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We begin with the dark matter accretion rate from [ref] and [ref] , which quantified the mass accretion histories of all dark matter halos with masses above $∼10^10$ M$_⊙$ in the two Millennium simulations of a $Λ$CDM universe [ref] .
The Merger Rates and Mass Assembly Histories of Dark Matter Haloes in the Two Millennium Simulations · Comparing $d/dt$ to Dark Matter Accretion Rate · 0.98
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The data points from these studies are plotted in Figures [ref] and [ref]: [ref] as purple diamonds and [ref] as green squares.
Very High Gas Fractions and Extended Gas Reservoirs in z=1.5 Disk Galaxies · Measurements at high z · 0.94
Compares with 1 paper
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They find MGDR values in agreement with the [ref] values at $z∼1.5$.
Very High Gas Fractions and Extended Gas Reservoirs in z=1.5 Disk Galaxies · Measurements at high z · 0.92
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