Magellan/M2FS Spectroscopy of Galaxy Clusters: Stellar Population Model and Application to Abell 267

Abstract

We report the results of a pilot program to use the Magellan/M2FS spectrograph to survey the galactic populations and internal kinematics of galaxy clusters. For this initial study, we present spectroscopic measurements for $223$ quiescent galaxies observed along the line of sight to the galaxy cluster Abell 267 ($z\sim 0.23$). We develop a Bayesian method for modeling the integrated light from each galaxy as a simple stellar population, with free parameters that specify redshift ($v_{\mathrm{los}}/c$) and characteristic age, metallicity ($[Fe/H]$), alpha-abundance ($[\alpha /\mathrm{Fe}]$), and internal velocity dispersion (${\sigma }_{\mathrm{int}}$) for individual galaxies. Parameter estimates derived from our 1.5-hour observation of A267 have median random errors of ${\sigma }_{v_{\mathrm{los}}}=20\mathrm{km}{\mathrm{s}}^{-1}$, ${\sigma }_{\mathrm{Age}}=1.2\mathrm{Gyr}$, ${\sigma }_{[Fe/H]}=0.11\mathrm{dex}$, ${\sigma }_{[\alpha /\mathrm{Fe}]}=0.07\mathrm{dex}$, and ${\sigma }_{{\sigma }_{\mathrm{int}}}=20\mathrm{km}{\mathrm{s}}^{-1}$. In a companion paper, we use these results to model the structure and internal kinematics of A267.

16 pages, 11 figures, accepted for publication in The Astronomical Journal

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Cited by in corpus (2)

• The effect of dynamical states on galaxy clusters populations. I. Classification of dynamical states
• Driving factors behind multiple populations