The influence of external environment at cosmic noon on the subsequent evolution of galaxy stellar mass

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Auteurs principaux: Gao, Tianmu, Mendel, J. Trevor, Kimmig, Lucas C., Lagos, Claudia del P., Remus, Rhea-Silvia, Wisnioski, Emily, Grasha, Kathryn
Format: Preprint
Publié: 2025
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author Gao, Tianmu
Mendel, J. Trevor
Kimmig, Lucas C.
Lagos, Claudia del P.
Remus, Rhea-Silvia
Wisnioski, Emily
Grasha, Kathryn
author_facet Gao, Tianmu
Mendel, J. Trevor
Kimmig, Lucas C.
Lagos, Claudia del P.
Remus, Rhea-Silvia
Wisnioski, Emily
Grasha, Kathryn
contents Connecting high-redshift galaxies to their low-redshift descendants is one of the most important and challenging tasks of galaxy evolution studies. In this work, we investigate whether incorporating high-redshift environmental factors improves the accuracy of matching high-redshift galaxies to their $z\sim0$ descendants, using data from the EAGLE and MAGNETICUM simulations. Using random forest regression, we evaluate the relative importance of a set of environmental metrics at $z\sim3$ in determining the stellar mass of descendant galaxies at $z\sim0$. We identify the spherical overdensity within 1 cMpc ($δ_{1,\mathrm{sp}}$) as the most important environmental predictor. Tracking galaxies at $z\sim3$ with similar initial stellar masses but different $δ_{1,\mathrm{sp}}$ values, we find that, across all mass bins in both simulations, high-density environments produce $z\sim0$ descendants with median stellar masses up to eight times higher than the descendants of galaxies in low-density environments. For galaxies with $M_{*}\lesssim10^{10}M_{\odot}$, the difference is attributable to more merger-induced mass growth in high-density environments, whereas for higher-mass galaxies, it results from a combination of enhanced in-situ star formation and greater external mass accretion. By assessing the importance of overdensity across multiple scales and redshifts, we find that at $z\gtrsim2$, environmental factors become as important as stellar mass in predicting the stellar mass of $z\sim0$ descendants. Compared to using stellar mass at $z\sim3$ alone, incorporating $δ_{1,\mathrm{sp}}$ reduces the scatter in the residuals between the predicted and actual stellar masses by approximately 20% in EAGLE and 35% in MAGNETICUM.
format Preprint
id arxiv_https___arxiv_org_abs_2512_06792
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The influence of external environment at cosmic noon on the subsequent evolution of galaxy stellar mass
Gao, Tianmu
Mendel, J. Trevor
Kimmig, Lucas C.
Lagos, Claudia del P.
Remus, Rhea-Silvia
Wisnioski, Emily
Grasha, Kathryn
Astrophysics of Galaxies
Connecting high-redshift galaxies to their low-redshift descendants is one of the most important and challenging tasks of galaxy evolution studies. In this work, we investigate whether incorporating high-redshift environmental factors improves the accuracy of matching high-redshift galaxies to their $z\sim0$ descendants, using data from the EAGLE and MAGNETICUM simulations. Using random forest regression, we evaluate the relative importance of a set of environmental metrics at $z\sim3$ in determining the stellar mass of descendant galaxies at $z\sim0$. We identify the spherical overdensity within 1 cMpc ($δ_{1,\mathrm{sp}}$) as the most important environmental predictor. Tracking galaxies at $z\sim3$ with similar initial stellar masses but different $δ_{1,\mathrm{sp}}$ values, we find that, across all mass bins in both simulations, high-density environments produce $z\sim0$ descendants with median stellar masses up to eight times higher than the descendants of galaxies in low-density environments. For galaxies with $M_{*}\lesssim10^{10}M_{\odot}$, the difference is attributable to more merger-induced mass growth in high-density environments, whereas for higher-mass galaxies, it results from a combination of enhanced in-situ star formation and greater external mass accretion. By assessing the importance of overdensity across multiple scales and redshifts, we find that at $z\gtrsim2$, environmental factors become as important as stellar mass in predicting the stellar mass of $z\sim0$ descendants. Compared to using stellar mass at $z\sim3$ alone, incorporating $δ_{1,\mathrm{sp}}$ reduces the scatter in the residuals between the predicted and actual stellar masses by approximately 20% in EAGLE and 35% in MAGNETICUM.
title The influence of external environment at cosmic noon on the subsequent evolution of galaxy stellar mass
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2512.06792