Abstract
The evolutionary histories of early-type galaxies (ETGs) are influenced by a complex interplay of internal processes and environmental effects. Stellar population analysis has suggested that more massive galaxies are more metal-rich and α-enhanced than low-mass galaxies. This observational fact is not easily reconciled with the hierarchical assembly of galaxies under the Λ-CDM model, which predicts that massive galaxies grow by accreting numerous lower-mass systems. If these lower-mass systems typically have lower α-enhancement, as suggested by field galaxy samples, then the accretion process should dilute the α-enhancement of massive galaxies. One possible resolution is to re-examine the impact of environment on galaxy evolution. Specifically, low-mass galaxies that fall into dense cluster environments may be quenched early, locking in high α-enhancement before being accreted onto more massive galaxies. This research aims to test the impact of environmental quenching using new deep optical spectroscopy of satellite galaxies in 20 groups and clusters at z~0.1. The sample covers a wide range of halo mass and projected distance from cluster centers. Through full spectral fitting, we can derive and analyze stellar ages, iron abundance, and α-enhancement for the targets, seeking to provide further observational support for the environmental impact on galaxy evolution.
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