(a) Metallicity function and relations between (b) metallicity and radial velocity, (c) metallicity and maximum distance from the Galactic plane,and (d)metallicity and variability period for RR Lyrae variables in the initial sample.The curve in the first graph is the maximum-likelihood approximation of the distribution using a sum of two normal curves with the indicated means,dispersions,and total numbers. The dashed vertical lines in the second and the third panels are &quat;eye estimates&quat; of the location of the abrupt increase in the scatter of Vr and Zmax at [Fe/H ]=-0.95.
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