Posterior probability distribution on (a) the velocity dispersion and (b) metallicity dispersion. The histograms show the number of accepted MCMC trials in bins of 0.03 km s⁻¹ for ﹩{\sigma }_{v}﹩ and 0.01 dex for ﹩\sigma ([\mathrm{Fe}/{\rm{H}}])﹩. The vertical dashed lines indicate confidence levels for the upper limit on ﹩{\sigma }_{v}﹩ in the top panel and the mean value for ﹩\sigma ([\mathrm{Fe}/{\rm{H}}])﹩ in the bottom panel. The metallicity dispersion is computed for all candidate member stars (black), excluding star 46 (magenta), and excluding both star 46 and star 31 (cyan). Star 46 is a likely member, but it is a binary and very α-poor. Star 31 is far from the galaxy center, and it is the most metal-rich star in the sample, but it passes every membership cut (Section 3.1).