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∼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 (vlos/c) and characteristic age,
metallicity ([Fe/H]), alpha-abundance ([α/Fe]), and
internal velocity dispersion (σint) for individual galaxies.
Parameter estimates derived from our 1.5-hour observation of A267 have median
random errors of σvlos=20kms−1,
σAge=1.2Gyr, $\sigma_{\mathrm{[Fe/H]}}=0.11\
\mathrm{dex},\sigma_{[\alpha/\mathrm{Fe}]}=0.07\ \mathrm{dex},and\sigma_{\sigma_\mathrm{int}}=20\ \mathrm{km\ s^{-1}}$. In a companion paper,
we use these results to model the structure and internal kinematics of A267.Comment: 16 pages, 11 figures, accepted for publication in The Astronomical
Journa