The Role of Cluster Environments in Quiescent Galaxy Stellar Halo Assembly

Abstract

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 $\le$ $z$ $\le$ 1.0 in a sample of 2,168 cluster and 94,479 field QGs of $\log M_{\star }\ge 9.66$. Extended emission is traced via rest-frame $g$-band surface brightness ($\hat{I}{¼}_g$) profiles extracted from deep HSC-SSP $grizy$ imaging. We study stellar halo assembly trends by linking median $\hat{I}{¼}_g$ profile evolution to the underlying mass growth in galaxy subpopulations. Over 0.1 $\le$ $z$ $\le$ 1.0, cluster QGs build up stellar haloes faster than field QGs, with a $\sim 23\%$ and $\sim 40\%$ larger increase in integrated stellar halo luminosity ($L_{halo}$) in the low-mass ($9.66\le \log M_{\star }<10.5$) and high-mass ($\log M_{\star }\ge 10.5$) samples, respectively. High-mass cluster QGs host more luminous stellar haloes than the field (mean cluster-to-field $L_{halo}$ ratio of $\sim 1.2$), while low-mass cluster QGs host less luminous stellar haloes (mean ratio of $\sim 0.87$). Among cluster QGs of $\log M_{\star }\ge 10$, $L_{halo}$ increases with host cluster mass, but decreases for cluster QGs of $\log M_{\star }<10$. These results suggest higher-mass cluster QGs ($\log M_{\star }\ge 10$) experience enhanced stellar halo growth over 0.1 $\le$ $z$ $\le$ 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 ($9.66\le \log M_{\star }<10$) 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.