The Role of Cluster Environments in Quiescent Galaxy Stellar Halo Assembly

TL;DR

This study investigates how cluster environments influence the assembly of stellar haloes in quiescent galaxies from redshift 0.1 to 1.0, revealing environment-dependent growth patterns and the role of mergers and stripping.

Contribution

It provides new insights into how cluster environments differentially affect stellar halo growth in quiescent galaxies based on their mass and cluster properties.

Findings

Cluster QGs build stellar haloes faster than field QGs.

High-mass cluster QGs have more luminous stellar haloes than the field.

Stellar halo luminosity increases with cluster mass for high-mass QGs.

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 $\leq$ $z$ $\leq$ 1.0 in a sample of 2,168 cluster and 94,479 field QGs of $\log M_{\star} \geq 9.66$. Extended emission is traced via rest-frame $g$-band surface brightness ($\mu_g$) profiles extracted from deep HSC-SSP $grizy$ imaging. We study stellar halo assembly trends by linking median $\mu_g$ profile evolution to the underlying mass growth in galaxy subpopulations. Over 0.1 $\leq$ $z$ $\leq$ 1.0, cluster QGs build up stellar haloes faster than field QGs, with a $\sim23\%$ and $\sim40\%$ larger increase in integrated stellar halo luminosity ($L_{halo}$) in the low-mass ($9.66 \leq \log M_{\star} < 10.5$) and high-mass ($\log M_{\star} \geq 10.5$) samples, respectively. High-mass cluster QGs host more luminous stellar haloes than the field (mean cluster-to-field $L_{halo}$ ratio of $\sim1.2$), while low-mass cluster QGs host less luminous stellar haloes (mean ratio of $\sim0.87$). Among cluster QGs of $\log M_{\star} \geq 10$, $L_{halo}$ increases with host cluster mass, but decreases for cluster QGs of $\log M_{\star} < 10$. These results suggest higher-mass cluster QGs ($\log M_{\star} \geq 10$) experience enhanced stellar halo growth over 0.1 $\leq$ $z$ $\leq$ 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 ($9.66 \leq \log M_{\star} < 10$) 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.