2026/04/30 by Devin J. Williams, Ivana Damjanov, Marcin Sawicki +6
#astro-ph.GA
External interactions drive galaxy stellar mass growth and morphological evolution. As stellar haloes-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 2,168 cluster and 94,479 field QGs of log M⋆ ≥ 9.66. Extended emission is traced via rest-frame g-band surface brightness (μg) profiles extracted from deep HSC-SSP grizy imaging. We study stellar halo assembly trends by linking median μg profile evolution to the underlying mass growth in galaxy subpopulations. Over 0.1 ≤ z ≤ 1.0, cluster QGs build up stellar haloes faster than field QGs, with a ∼23% and ∼40% larger increase in integrated stellar halo luminosity (Lhalo) 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 haloes than the field (mean cluster-to-field Lhalo ratio of ∼1.2), while low-mass cluster QGs host less luminous stellar haloes (mean ratio of ∼0.87). Among cluster QGs of log M⋆ ≥ 10, Lhalo 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 pre-infall 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.