Redshift-dependent galaxy formation efficiency at $z=5-13$ in the FirstLight simulations

Fuente: arXiv
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Auteurs principaux: Ceverino, Daniel, Nakazato, Yurina, Yoshida, Naoki, Klessen, Ralf, Glover, Simon
Format: Preprint
Publié: 2024
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author Ceverino, Daniel
Nakazato, Yurina
Yoshida, Naoki
Klessen, Ralf
Glover, Simon
author_facet Ceverino, Daniel
Nakazato, Yurina
Yoshida, Naoki
Klessen, Ralf
Glover, Simon
contents Current models of the formation of first galaxies predict low masses and faint objects at extremely high redshifts, z=9-15. However, the first observations of this epoch indicate a higher-than-expected number of bright (sometimes massive) galaxies. Numerical simulations can help to elucidate the mild evolution of the bright end of the UV luminosity function and they can provide the link between the evolution of bright galaxies and variations of the galaxy formation efficiency across different redshifts. We use the FirstLight database of 377 zoom-in cosmological simulations of a mass-complete sample of galaxies. Mock luminosities are estimated by a dust model constrained by current observations of an evolution of the beta-MUV relation at high-z. FirstLight contains a high number of bright galaxies, MUV<-20, consistent with current data at z=6-13. The evolution of the UV cosmic density is driven by the evolution of the galaxy efficiency and the relation between MUV and halo mass. The efficiency of galaxy formation increases significantly with redshift at a fixed halo mass because galactic halos at extremely high redshifts convert gas into stars at a higher rate than at lower redshifts. The high gas densities in galaxies at z>9 enable these high efficiencies. Our simulations predict higher number densities of massive galaxies, Ms=10^9 Msun, than other models with constant efficiency. Cosmological simulations of galaxy formation with self-consistent models of star formation and feedback can reproduce the different regimes of galaxy formation across cosmic history.
format Preprint
id arxiv_https___arxiv_org_abs_2404_02537
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Redshift-dependent galaxy formation efficiency at $z=5-13$ in the FirstLight simulations
Ceverino, Daniel
Nakazato, Yurina
Yoshida, Naoki
Klessen, Ralf
Glover, Simon
Astrophysics of Galaxies
Current models of the formation of first galaxies predict low masses and faint objects at extremely high redshifts, z=9-15. However, the first observations of this epoch indicate a higher-than-expected number of bright (sometimes massive) galaxies. Numerical simulations can help to elucidate the mild evolution of the bright end of the UV luminosity function and they can provide the link between the evolution of bright galaxies and variations of the galaxy formation efficiency across different redshifts. We use the FirstLight database of 377 zoom-in cosmological simulations of a mass-complete sample of galaxies. Mock luminosities are estimated by a dust model constrained by current observations of an evolution of the beta-MUV relation at high-z. FirstLight contains a high number of bright galaxies, MUV<-20, consistent with current data at z=6-13. The evolution of the UV cosmic density is driven by the evolution of the galaxy efficiency and the relation between MUV and halo mass. The efficiency of galaxy formation increases significantly with redshift at a fixed halo mass because galactic halos at extremely high redshifts convert gas into stars at a higher rate than at lower redshifts. The high gas densities in galaxies at z>9 enable these high efficiencies. Our simulations predict higher number densities of massive galaxies, Ms=10^9 Msun, than other models with constant efficiency. Cosmological simulations of galaxy formation with self-consistent models of star formation and feedback can reproduce the different regimes of galaxy formation across cosmic history.
title Redshift-dependent galaxy formation efficiency at $z=5-13$ in the FirstLight simulations
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2404.02537