A Consistent Comparison of Intracluster Light Assembly in Simulations I. Redshift Evolution and Progenitor Galaxies
Abstract
The tidal stripping of satellite galaxies and the stellar detritus ejected during galaxy mergers builds up a diffuse stellar component in galaxy clusters known as the intracluster light (ICL). We investigate ICL assembly in cluster-mass haloes (M178c∼1014−1015 M⊙) using four different hydrodynamical simulations (Horizon-AGN, TNG100, The Three Hundred Gizmo-Simba 7K, and Hydrangea) under a homogenized ICL identification framework. For our fiducial ICL definition we obtain broadly consistent z≈0 ICL stellar mass fractions (∼0.1−0.2) and, by tracking the progenitors of z≈0 clusters back to z≳2, find no significant evolution in average ICL mass fractions. Alternative approaches for distinguishing the ICL from the central galaxy show the absolute ICL fraction to be highly sensitive to adopted definition, but we never find any significant inter-simulation discrepancies when implementing a consistent methodology to identify the ICL. Whether the average ICL mass fraction falls with increasing redshift or does not evolve is determined by the ICL definition adopted. By tracing z≈0 ICL stars back to their progenitor galaxies, we find that lower-mass satellites typically make slightly larger ICL contributions relative to their mass in every considered simulation, but which galaxies make the dominant contribution to the ICL is primarily controlled by the infalling satellite mass function. Most ICL stars sourced from satellite galaxies are therefore expected to originate from galaxies with infall stellar masses above ∼1010 M⊙ and largely within 1010.5−1011.5 M⊙.
Versions
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BibTeX
@misc{brown2026consistent,
title = {{A Consistent Comparison of Intracluster Light Assembly in Simulations I. Redshift Evolution and Progenitor Galaxies}},
author = {Harley J. Brown and Garreth Martin and Frazer R. Pearce and Yannick M. Bahé and Madeline Butler and Weiguang Cui and Nina A. Hatch and Alexander Knebe},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.20175},
eprint = {2606.20175},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.20175},
}
RIS
TY - UNPB
TI - A Consistent Comparison of Intracluster Light Assembly in Simulations I. Redshift Evolution and Progenitor Galaxies
AU - Harley J. Brown
AU - Garreth Martin
AU - Frazer R. Pearce
AU - Yannick M. Bahé
AU - Madeline Butler
AU - Weiguang Cui
AU - Nina A. Hatch
AU - Alexander Knebe
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2606.20175
UR - https://arxiv.org/abs/2606.20175
AB - The tidal stripping of satellite galaxies and the stellar detritus ejected during galaxy mergers builds up a diffuse stellar component in galaxy clusters known as the intracluster light (ICL). We investigate ICL assembly in cluster-mass haloes (M_178c∼10^14−10^15 M_⊙) using four different hydrodynamical simulations (Horizon-AGN, TNG100, The Three Hundred Gizmo-Simba 7K, and Hydrangea) under a homogenized ICL identification framework. For our fiducial ICL definition we obtain broadly consistent z≈0 ICL stellar mass fractions (∼0.1−0.2) and, by tracking the progenitors of z≈0 clusters back to z≳2, find no significant evolution in average ICL mass fractions. Alternative approaches for distinguishing the ICL from the central galaxy show the absolute ICL fraction to be highly sensitive to adopted definition, but we never find any significant inter-simulation discrepancies when implementing a consistent methodology to identify the ICL. Whether the average ICL mass fraction falls with increasing redshift or does not evolve is determined by the ICL definition adopted. By tracing z≈0 ICL stars back to their progenitor galaxies, we find that lower-mass satellites typically make slightly larger ICL contributions relative to their mass in every considered simulation, but which galaxies make the dominant contribution to the ICL is primarily controlled by the infalling satellite mass function. Most ICL stars sourced from satellite galaxies are therefore expected to originate from galaxies with infall stellar masses above ∼10^10 M_⊙ and largely within 10^10.5−10^11.5 M_⊙.
ER -