TY - JOUR
T1 - NeutralUniverseMachine
T2 - An Empirical Model for the Evolution of H i and H2 Gas in the Universe
AU - Guo, Hong
AU - Wang, Jing
AU - Jones, Michael G.
AU - Behroozi, Peter
N1 - Funding Information: We thank the anonymous reviewer for helpful suggestions that significantly improve the presentation of this paper. This work is supported by the National SKA Program of China (grant No. 2020SKA0110100), the National Natural Science Foundation of China (Nos. 11922305, 11833005, 12073002, 11721303, 12011530159), the CAS Project for Young Scientists in Basic Research (No. YSBR-092), and the science research grants from the China Manned Space Project with Nos. CMS-CSST-2021-A02 and CMS-CSST-2021-B01. We thank Toby Brown, Nissim Kanekar, and Kasper E. Heintz for helpful discussions. We acknowledge the use of the High Performance Computing Resource in the Core Facility for Advanced Research Computing at the Shanghai Astronomical Observatory. Publisher Copyright: © 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/9/1
Y1 - 2023/9/1
N2 - Accurately modeling the cold gas content in the universe is challenging for current theoretical models. We propose a new empirical model NeutralUniverseMachine for the evolution of H i and H2 gas along with dark matter halos based on the UniverseMachine catalog. It is able to accurately describe the observed H i and H2 mass functions, molecular-to-atomic ratio, H i-halo mass relation, H i/H2-stellar mass relations at z ∼ 0, as well as the evolution of cosmic gas densities ρ H I and ρ H 2 at 0 < z < 6. The predictions from our model include the following: (i) There is weak evolution of H i mass function at 0 < z < 3, but the evolution of H2 mass function is much stronger at the massive end. (ii) The average H i and H2 masses at a given stellar mass decrease by around 1 dex since z = 3 for the star-forming galaxies, but the evolution for the quenched galaxies is much weaker. (iii) Star-forming galaxies have a varying H i depletion time τ H I from 0.1-10 Gyr, and the dependence of τ H I on stellar mass and redshift is much stronger than those of the H2 depletion time. The quenched galaxies have a much longer gas depletion time and weaker redshift evolution. (iv) The cosmic baryon density associated with galaxies is dominated by stars at z < 1.2 and mainly contributed by H i gas at higher redshifts. (v) The H i bias gradually increases with the redshift from 0.69 to 2.33 at 0 < z < 3 and is consistent with recent H i intensity mapping experiments.
AB - Accurately modeling the cold gas content in the universe is challenging for current theoretical models. We propose a new empirical model NeutralUniverseMachine for the evolution of H i and H2 gas along with dark matter halos based on the UniverseMachine catalog. It is able to accurately describe the observed H i and H2 mass functions, molecular-to-atomic ratio, H i-halo mass relation, H i/H2-stellar mass relations at z ∼ 0, as well as the evolution of cosmic gas densities ρ H I and ρ H 2 at 0 < z < 6. The predictions from our model include the following: (i) There is weak evolution of H i mass function at 0 < z < 3, but the evolution of H2 mass function is much stronger at the massive end. (ii) The average H i and H2 masses at a given stellar mass decrease by around 1 dex since z = 3 for the star-forming galaxies, but the evolution for the quenched galaxies is much weaker. (iii) Star-forming galaxies have a varying H i depletion time τ H I from 0.1-10 Gyr, and the dependence of τ H I on stellar mass and redshift is much stronger than those of the H2 depletion time. The quenched galaxies have a much longer gas depletion time and weaker redshift evolution. (iv) The cosmic baryon density associated with galaxies is dominated by stars at z < 1.2 and mainly contributed by H i gas at higher redshifts. (v) The H i bias gradually increases with the redshift from 0.69 to 2.33 at 0 < z < 3 and is consistent with recent H i intensity mapping experiments.
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U2 - 10.3847/1538-4357/aced47
DO - 10.3847/1538-4357/aced47
M3 - Article
SN - 0004-637X
VL - 955
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 57
ER -