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Main Authors: Nishigaki, Moka, Behroozi, Peter, Ouchi, Masami, Guo, Hong, Somerville, Rachel S., Gallazzi, Anna R., Nakajima, Kimihiko, Watanabe, Kuria
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2503.10999
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author Nishigaki, Moka
Behroozi, Peter
Ouchi, Masami
Guo, Hong
Somerville, Rachel S.
Gallazzi, Anna R.
Nakajima, Kimihiko
Watanabe, Kuria
author_facet Nishigaki, Moka
Behroozi, Peter
Ouchi, Masami
Guo, Hong
Somerville, Rachel S.
Gallazzi, Anna R.
Nakajima, Kimihiko
Watanabe, Kuria
contents We present an empirical chemical evolution model that explains the distribution of metals in the interstellar medium (ISM) and the circumgalactic medium (CGM) of galaxies based on the UniverseMachine and NeutralUniverseMachine models in the framework of $Λ$CDM structure formation. We parameterize the fractions of outflowing metals returned and mixed into the multi-phase ISM of the star-forming regions ($f_{\rm H2}$) and into the neutral gas regions ($f_{\rm HI}$); metal production, transfer, and dilution are caused by star formation, galaxy mergers, and gas inflow from the inter-galactic medium, respectively, with rates determined by the (Neutral)UniverseMachine models. Using a Markov Chain Monte Carlo algorithm, we explore the posterior distributions of metal return and mixing consistent with observed mass-metallicity relations in HII regions (at $0<z<5$), HI damped Lyman-alpha systems (at $1<z<4$), and the CGM (at $z=0$). We find that the fraction of metals present in the ISM, $f_{\rm H2}+f_{\rm HI}$, increases with halo mass from $\sim20$\% at $10^{10}M_\odot$ to $\sim80$\% at $10^{13}M_\odot$. These fractions increase mildly at higher redshifts, to $\sim30$\% at $10^{10}M_\odot$ and $\sim80$\% at $10^{13}M_\odot$ at $z=5$. Interestingly, there is no significant redshift evolution of $f_{\rm H2}+f_{\rm HI}$ at fixed circular velocity, suggesting that metal distribution between the ISM and CGM is universally determined by the halo potential well depth. CGM metal enrichment is thus slow in high-$z$ halos with deep potential wells. While $f_{\rm H2}$ monotonically increases with halo mass, $f_{\rm HI}$ peaks at $\sim10^{12}-10^{13} M_\odot$, suggesting that reinfall may be inefficient in larger-mass halos.
format Preprint
id arxiv_https___arxiv_org_abs_2503_10999
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle ChemicalUniverseMachine I: Uncovering the Cosmic Evolution of Metals in the Galaxy-ISM-CGM Ecosystem
Nishigaki, Moka
Behroozi, Peter
Ouchi, Masami
Guo, Hong
Somerville, Rachel S.
Gallazzi, Anna R.
Nakajima, Kimihiko
Watanabe, Kuria
Astrophysics of Galaxies
We present an empirical chemical evolution model that explains the distribution of metals in the interstellar medium (ISM) and the circumgalactic medium (CGM) of galaxies based on the UniverseMachine and NeutralUniverseMachine models in the framework of $Λ$CDM structure formation. We parameterize the fractions of outflowing metals returned and mixed into the multi-phase ISM of the star-forming regions ($f_{\rm H2}$) and into the neutral gas regions ($f_{\rm HI}$); metal production, transfer, and dilution are caused by star formation, galaxy mergers, and gas inflow from the inter-galactic medium, respectively, with rates determined by the (Neutral)UniverseMachine models. Using a Markov Chain Monte Carlo algorithm, we explore the posterior distributions of metal return and mixing consistent with observed mass-metallicity relations in HII regions (at $0<z<5$), HI damped Lyman-alpha systems (at $1<z<4$), and the CGM (at $z=0$). We find that the fraction of metals present in the ISM, $f_{\rm H2}+f_{\rm HI}$, increases with halo mass from $\sim20$\% at $10^{10}M_\odot$ to $\sim80$\% at $10^{13}M_\odot$. These fractions increase mildly at higher redshifts, to $\sim30$\% at $10^{10}M_\odot$ and $\sim80$\% at $10^{13}M_\odot$ at $z=5$. Interestingly, there is no significant redshift evolution of $f_{\rm H2}+f_{\rm HI}$ at fixed circular velocity, suggesting that metal distribution between the ISM and CGM is universally determined by the halo potential well depth. CGM metal enrichment is thus slow in high-$z$ halos with deep potential wells. While $f_{\rm H2}$ monotonically increases with halo mass, $f_{\rm HI}$ peaks at $\sim10^{12}-10^{13} M_\odot$, suggesting that reinfall may be inefficient in larger-mass halos.
title ChemicalUniverseMachine I: Uncovering the Cosmic Evolution of Metals in the Galaxy-ISM-CGM Ecosystem
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2503.10999