A Splashback-like Feature of Central Galaxies in Galaxy Clusters

Fuente: arXiv
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Main Authors: Zhang, Yuanyuan, Adhikari, Susmita, Edwards, Louise O. V., Golden-Marx, Jesse B., Ogando, Ricardo L. C., Rykoff, Eli S.
Format: Preprint
Published: 2025
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author Zhang, Yuanyuan
Adhikari, Susmita
Edwards, Louise O. V.
Golden-Marx, Jesse B.
Ogando, Ricardo L. C.
Rykoff, Eli S.
author_facet Zhang, Yuanyuan
Adhikari, Susmita
Edwards, Louise O. V.
Golden-Marx, Jesse B.
Ogando, Ricardo L. C.
Rykoff, Eli S.
contents We investigate a splashback-like feature in the outer region of central galaxies (CGs) in clusters. This feature is detected as a "dip" in the radial slope of the CG surface brightness, derived through the stacking of Dark Energy Survey data of over four thousand galaxy clusters in the redshift range of 0.2 to 0.5 with richness 20 and above. The local minimum of the dip occurs between 40 to 60 kpc from the CG center, with a mild dependence on cluster richness. This feature resembles the density transition caused by the splashback effect at the outskirts of galaxy clusters, when accreted matter reaches the apocenter for the first time. We turn to the IllustrisTNG hydro-dynamic simulation to gain theoretical insights. Density bumps, shells and accretion streaks are identified in the diffuse stellar content of the CGs and intra-cluster light which relate to the recent history of disruption and accretion. These features occur at the outskirts of the CGs, up to several hundred kiloparsecs from the cluster center. Thus, the location of the splashback-like dip in the data potentially marks the edge of the CG and the beginning of a region with the cluster diffuse light undergoing active or recent accretion.
format Preprint
id arxiv_https___arxiv_org_abs_2509_22780
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Splashback-like Feature of Central Galaxies in Galaxy Clusters
Zhang, Yuanyuan
Adhikari, Susmita
Edwards, Louise O. V.
Golden-Marx, Jesse B.
Ogando, Ricardo L. C.
Rykoff, Eli S.
Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
We investigate a splashback-like feature in the outer region of central galaxies (CGs) in clusters. This feature is detected as a "dip" in the radial slope of the CG surface brightness, derived through the stacking of Dark Energy Survey data of over four thousand galaxy clusters in the redshift range of 0.2 to 0.5 with richness 20 and above. The local minimum of the dip occurs between 40 to 60 kpc from the CG center, with a mild dependence on cluster richness. This feature resembles the density transition caused by the splashback effect at the outskirts of galaxy clusters, when accreted matter reaches the apocenter for the first time. We turn to the IllustrisTNG hydro-dynamic simulation to gain theoretical insights. Density bumps, shells and accretion streaks are identified in the diffuse stellar content of the CGs and intra-cluster light which relate to the recent history of disruption and accretion. These features occur at the outskirts of the CGs, up to several hundred kiloparsecs from the cluster center. Thus, the location of the splashback-like dip in the data potentially marks the edge of the CG and the beginning of a region with the cluster diffuse light undergoing active or recent accretion.
title A Splashback-like Feature of Central Galaxies in Galaxy Clusters
topic Astrophysics of Galaxies
Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2509.22780