The stellar mass composition of galaxy clusters and dependencies on dark matter halo properties

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Hauptverfasser: Montenegro-Taborda, Daniel, Avila-Reese, Vladimir, Rodriguez-Gomez, Vicente, Manuwal, Aditya, Cervantes-Sodi, Bernardo
Format: Preprint
Veröffentlicht: 2025
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author Montenegro-Taborda, Daniel
Avila-Reese, Vladimir
Rodriguez-Gomez, Vicente
Manuwal, Aditya
Cervantes-Sodi, Bernardo
author_facet Montenegro-Taborda, Daniel
Avila-Reese, Vladimir
Rodriguez-Gomez, Vicente
Manuwal, Aditya
Cervantes-Sodi, Bernardo
contents We analyze 700 clusters from the TNG300 hydrodynamical simulation ($M_{200}\geq5\times10^{13} \,M_{\odot}$ at (z=0)) to examine the radial stellar mass distribution of their central objects, consisting of the brightest cluster galaxy (BCG) and the intracluster light (ICL). The BCG+ICL mass fraction weakly anticorrelates with $M_{200}$, but strongly correlates with the concentration, $c_{200}$, the assembly redshift, $z_{50}$, and the mass gap between the most massive and the fourth more massive member, $ΔM_{\rm \ast, 4th}$. We explore different aperture radii to nominally separate the ICL from the BCG and calculate ICL fractions. For $r_{\rm{ap}}=2r_{\rm half}$, where $r_{\rm half}$ is the radius containing half the BCG+ICL mass, the ICL fraction is nearly independent of $M_{200}$, $c_{200}$, and $z_{50}$ with values $M_{\ast,\rm ICL}/(M_{\ast,\rm ICL}+M_{\ast,\rm BCG})= 0.33\pm0.03$. Including the stellar mass of the satellites, the fraction $M_{\ast,\rm ICL}/(M_{\ast,\rm ICL}+M_{\ast,\rm BCG}+M_{\rm \ast,sat})$ weakly anticorrelates with $M_{200}$ and strongly correlates with $c_{200}$, $z_{50}$, and $ΔM_{\rm \ast, 4th}$, suggesting that in more concentrated/earlier assembled/more relaxed clusters more stellar mass is lost from the satellites (by tidal stripping, and mergers) in favour of the ICL and BCG. Indeed, we find that ex-situ stars dominate both in the BCG and ICL masses, with mergers contributing more to the BCG, while tidal stripping contributes more to the ICL. We find that the difference between the projected and 3D ICL fractions are only a few per cent and suggest using $2r_{\rm half}$ to separate the ICL from the BCG in observed clusters.
format Preprint
id arxiv_https___arxiv_org_abs_2502_07927
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The stellar mass composition of galaxy clusters and dependencies on dark matter halo properties
Montenegro-Taborda, Daniel
Avila-Reese, Vladimir
Rodriguez-Gomez, Vicente
Manuwal, Aditya
Cervantes-Sodi, Bernardo
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
We analyze 700 clusters from the TNG300 hydrodynamical simulation ($M_{200}\geq5\times10^{13} \,M_{\odot}$ at (z=0)) to examine the radial stellar mass distribution of their central objects, consisting of the brightest cluster galaxy (BCG) and the intracluster light (ICL). The BCG+ICL mass fraction weakly anticorrelates with $M_{200}$, but strongly correlates with the concentration, $c_{200}$, the assembly redshift, $z_{50}$, and the mass gap between the most massive and the fourth more massive member, $ΔM_{\rm \ast, 4th}$. We explore different aperture radii to nominally separate the ICL from the BCG and calculate ICL fractions. For $r_{\rm{ap}}=2r_{\rm half}$, where $r_{\rm half}$ is the radius containing half the BCG+ICL mass, the ICL fraction is nearly independent of $M_{200}$, $c_{200}$, and $z_{50}$ with values $M_{\ast,\rm ICL}/(M_{\ast,\rm ICL}+M_{\ast,\rm BCG})= 0.33\pm0.03$. Including the stellar mass of the satellites, the fraction $M_{\ast,\rm ICL}/(M_{\ast,\rm ICL}+M_{\ast,\rm BCG}+M_{\rm \ast,sat})$ weakly anticorrelates with $M_{200}$ and strongly correlates with $c_{200}$, $z_{50}$, and $ΔM_{\rm \ast, 4th}$, suggesting that in more concentrated/earlier assembled/more relaxed clusters more stellar mass is lost from the satellites (by tidal stripping, and mergers) in favour of the ICL and BCG. Indeed, we find that ex-situ stars dominate both in the BCG and ICL masses, with mergers contributing more to the BCG, while tidal stripping contributes more to the ICL. We find that the difference between the projected and 3D ICL fractions are only a few per cent and suggest using $2r_{\rm half}$ to separate the ICL from the BCG in observed clusters.
title The stellar mass composition of galaxy clusters and dependencies on dark matter halo properties
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2502.07927