Stellar Population Gradients of Galaxies Across Mass and Environment

Leader: Joon Hyeop Lee

Collaborators: Minje Beom, Hyunjin Jeong, Mina Pak, Jiwon Chung (and more?)

Topic: The future fate of ram-pressure affected cluster galaxies

Status: under review by Science Committee

Abstract: The radial gradient of stellar populations (age, metallicity, and α-abundance) in a galaxy reflects its formation history, including merger characteristics (wet vs. dry, and minor vs. major) and the processes of star formation and quenching (inside-out vs. outside-in). Although numerous studies have already explored these topics, spectroscopic investigations of stellar population gradients out to 2 effective radii (Re) for a large sample have been rare, especially for cluster galaxies. We propose a systematic study of the stellar population gradients of galaxies, utilising the capabilities of the Hector Galaxy Survey: its broad spatial coverage and dense sampling of galaxies in and around selected galaxy clusters. We plan to bin each galaxy cube into inner (R ≤ Re) and outer (Re < R ≤ 2Re) elliptical regions and to estimate stellar populations in each bin using full spectrum fitting or absorption line analysis. By comparing the derived stellar population gradients across different environments (e.g., locations in the phase-space diagram), we aim to better constrain the mass assembly, star formation and quenching histories of galaxies as a function of stellar mass and environment.

Needed data products: structural parameters (Re, PA, axis ratio), environmental parameters (phase-space information, local density), stellar mass

Publication Date: 01/01/2026