Work

The Role of Cluster Environments in Quiescent Galaxy Stellar Halo Assembly

Year: 2026

Type: article

Abstract: External interactions drive galaxy stellar mass growth and morphological evolution. As stellar halos—assembled largely via hierarchical accretion—preserve signatures of these processes, their growth probes how environment regulates galaxy evolution. We investigate how cluster environments influence quiescent galaxy (QG) stellar halo assembly over 0.1 ≤ z ≤ 1.0 in a sample of 2168 cluster and 94,479 field QGs of log M ⋆ ≥ 9.66 . Extended emission is traced via rest-frame g -band surface brightness ( μ g ) profiles extracted from deep Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) grizy imaging. We study stellar halo assembly trends by linking median μ g profile evolution to the underlying mass growth in galaxy subpopulations. Over 0.1 ≤ z ≤ 1.0, cluster QGs build up stellar halos faster than field QGs, with a ∼23% and ∼40% larger increase in integrated stellar halo luminosity ( L halo ) in the low-mass ( 9.66 ≤ log M ⋆ < 10.5 ) and high-mass ( log M ⋆ ≥ 10.5 ) samples, respectively. High-mass cluster QGs host more luminous stellar halos than the field (mean cluster-to-field L halo ratio of ∼1.2), while low-mass cluster QGs host less luminous stellar halos than their field counterparts (mean ratio of ∼0.87). Among cluster QGs of log M ⋆ ≥ 10 , L halo increases with host cluster mass, but decreases for cluster QGs of log M ⋆ < 10 . These results suggest higher-mass cluster QGs ( log M ⋆ ≥ 10 ) experience enhanced stellar halo growth over 0.1 ≤ z ≤ 1.0 fueled by increased merger-driven accretion, likely from minor mergers in cluster outskirts or in preinfall group and filament environments. Lower-mass cluster QGs ( 9.66 ≤ log M ⋆ < 10 ) instead have suppressed stellar halo growth in clusters and likely lose outer stellar material to environmental stripping or accretion by high-mass galaxies during mergers.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/ae95fc