Igniting galaxy formation in the post-reionization universe

Fuente: arXiv
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Main Authors: Moreno, Jorge, Wheeler, Coral, Mercado, Francisco J., Wimberly, M. Katy Rodriguez, Samuel, Jenna, Gandhi, Pratik J., Cenci, Elia, Feldmann, Robert, Boylan-Kolchin, Michael, Wetzel, Andrew, Bullock, James S., Hopkins, Philip F.
Format: Preprint
Published: 2025
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author Moreno, Jorge
Wheeler, Coral
Mercado, Francisco J.
Wimberly, M. Katy Rodriguez
Samuel, Jenna
Gandhi, Pratik J.
Cenci, Elia
Feldmann, Robert
Boylan-Kolchin, Michael
Wetzel, Andrew
Bullock, James S.
Hopkins, Philip F.
author_facet Moreno, Jorge
Wheeler, Coral
Mercado, Francisco J.
Wimberly, M. Katy Rodriguez
Samuel, Jenna
Gandhi, Pratik J.
Cenci, Elia
Feldmann, Robert
Boylan-Kolchin, Michael
Wetzel, Andrew
Bullock, James S.
Hopkins, Philip F.
contents It is widely believed that the ultraviolet background produced during the epoch of reionization conspires against the formation of low-mass galaxies. Indeed, this mechanism is often invoked as a solution to the so-called `missing satellites problem.' In this paper we employ FIREbox, a large-volume cosmological simulation based on the Feedback In Realistic Environments (FIRE-2) physics model, to characterize the mechanisms governing galaxy ignition in the post-reionization era. By carefully matching recently-ignited halos (with stellar ages below $100$ Myr at the time of selection) to halos that failed to form any stars, we conclude that the presence of cold-dense gas and halo concentration help incite the process of galaxy formation. Concretely, we find that $100\%$ of recently-ignited halos experience cold-dense gas enhancements relative to their matched failed counterparts. Likewise, approximately $83\%$ display enhancements in both cold-dense gas and Navarro-Frenk-White concentration ($c_{\rm NFW}$), while the remaining $\sim17\%$ exhibit enhanced cold-dense gas content and suppressed $c_{\rm NFW}$ values. Lastly, our simulation suggests that galaxy ignition can occur as late as $z=2$, potentially allowing us to observationally catch this process `in the act' in the foreseeable future.
format Preprint
id arxiv_https___arxiv_org_abs_2511_03785
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Igniting galaxy formation in the post-reionization universe
Moreno, Jorge
Wheeler, Coral
Mercado, Francisco J.
Wimberly, M. Katy Rodriguez
Samuel, Jenna
Gandhi, Pratik J.
Cenci, Elia
Feldmann, Robert
Boylan-Kolchin, Michael
Wetzel, Andrew
Bullock, James S.
Hopkins, Philip F.
Astrophysics of Galaxies
It is widely believed that the ultraviolet background produced during the epoch of reionization conspires against the formation of low-mass galaxies. Indeed, this mechanism is often invoked as a solution to the so-called `missing satellites problem.' In this paper we employ FIREbox, a large-volume cosmological simulation based on the Feedback In Realistic Environments (FIRE-2) physics model, to characterize the mechanisms governing galaxy ignition in the post-reionization era. By carefully matching recently-ignited halos (with stellar ages below $100$ Myr at the time of selection) to halos that failed to form any stars, we conclude that the presence of cold-dense gas and halo concentration help incite the process of galaxy formation. Concretely, we find that $100\%$ of recently-ignited halos experience cold-dense gas enhancements relative to their matched failed counterparts. Likewise, approximately $83\%$ display enhancements in both cold-dense gas and Navarro-Frenk-White concentration ($c_{\rm NFW}$), while the remaining $\sim17\%$ exhibit enhanced cold-dense gas content and suppressed $c_{\rm NFW}$ values. Lastly, our simulation suggests that galaxy ignition can occur as late as $z=2$, potentially allowing us to observationally catch this process `in the act' in the foreseeable future.
title Igniting galaxy formation in the post-reionization universe
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2511.03785