The influence of baryons on low-mass haloes

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Auteurs principaux: Zheng, Haonan, Bose, Sownak, Frenk, Carlos S., Gao, Liang, Jenkins, Adrian, Liao, Shihong, Springel, Volker, Wang, Jie, White, Simon D. M.
Format: Preprint
Publié: 2024
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author Zheng, Haonan
Bose, Sownak
Frenk, Carlos S.
Gao, Liang
Jenkins, Adrian
Liao, Shihong
Springel, Volker
Wang, Jie
White, Simon D. M.
author_facet Zheng, Haonan
Bose, Sownak
Frenk, Carlos S.
Gao, Liang
Jenkins, Adrian
Liao, Shihong
Springel, Volker
Wang, Jie
White, Simon D. M.
contents The Voids-within-Voids-within-Voids (VVV) project used dark-matter-only simulations to study the abundance and structure of dark matter haloes over the full mass range populated in the standard $Λ\mathrm{CDM}$ cosmology. Here we explore how baryonic effects modify these results for $z=0$ halo masses in the range $10^4$ to $10^7~\mathrm{M_\odot}$, below the threshold for galaxy formation. Our main study focuses on three simulations from identical initial conditions at $z=127$, one following dark matter only, one including non-radiative gas, and one additionally including the baryonic physics relevant in this halo mass range (cooling and photoheating). In the non-radiative simulation, above $10^{5.5}~\mathrm{M_\odot}$, halo abundance and internal structure are very similar to the dark-matter-only simulation, and the baryon to dark matter ratio is everywhere close to the cosmic value. At lower mass, this ratio drops and haloes are less concentrated and less massive in the non-radiative case. Test simulations at higher resolution show this to be mainly a resolution effect; the expected drop in baryon content due to residual pressure effects only becomes substantial for $z=0$ haloes below $\sim 10^{2.7}~\mathrm{M_\odot}$. However, gas is heated by reionization at $z=6$ in our "full physics" run, and this results in almost complete expulsion of gas from all haloes in our simulated mass range. This suppresses the halo mass function by $\sim 30 \%$, lowers halo concentration, and consequently weakens the dark matter annihilation signal by $\sim 40-60 \%$.
format Preprint
id arxiv_https___arxiv_org_abs_2403_17044
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The influence of baryons on low-mass haloes
Zheng, Haonan
Bose, Sownak
Frenk, Carlos S.
Gao, Liang
Jenkins, Adrian
Liao, Shihong
Springel, Volker
Wang, Jie
White, Simon D. M.
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
The Voids-within-Voids-within-Voids (VVV) project used dark-matter-only simulations to study the abundance and structure of dark matter haloes over the full mass range populated in the standard $Λ\mathrm{CDM}$ cosmology. Here we explore how baryonic effects modify these results for $z=0$ halo masses in the range $10^4$ to $10^7~\mathrm{M_\odot}$, below the threshold for galaxy formation. Our main study focuses on three simulations from identical initial conditions at $z=127$, one following dark matter only, one including non-radiative gas, and one additionally including the baryonic physics relevant in this halo mass range (cooling and photoheating). In the non-radiative simulation, above $10^{5.5}~\mathrm{M_\odot}$, halo abundance and internal structure are very similar to the dark-matter-only simulation, and the baryon to dark matter ratio is everywhere close to the cosmic value. At lower mass, this ratio drops and haloes are less concentrated and less massive in the non-radiative case. Test simulations at higher resolution show this to be mainly a resolution effect; the expected drop in baryon content due to residual pressure effects only becomes substantial for $z=0$ haloes below $\sim 10^{2.7}~\mathrm{M_\odot}$. However, gas is heated by reionization at $z=6$ in our "full physics" run, and this results in almost complete expulsion of gas from all haloes in our simulated mass range. This suppresses the halo mass function by $\sim 30 \%$, lowers halo concentration, and consequently weakens the dark matter annihilation signal by $\sim 40-60 \%$.
title The influence of baryons on low-mass haloes
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2403.17044