Abstract
ABSTRACT Radial velocity curves are presented for the RR Lyrae stars V1 and V3 in the low metallicity globular cluster M92 (NGC 6341) and V8 and V28 in the intermediate metallicity globular cluster M5 (NGC 5904) based on between 50 and 90 observations per star. The radial velocities were derived by cross correlating spectra obtained with the Multiple Mirror Telescope echelle spectrograph with synthetic templates calculated using Kurucz's model atmospheres (ATLAS8) and synthetic spectrum (SYNTHE) codes. The synthetic templates provide a better match to the observed spectra than the available observed templates, especially for the metal-poor stars, resulting in high precision radial velocities good to a few km s-1 in most cases. We find systemic velocities of -125.4, -122.6, +48.7 and +53.6 km s-1 for M92-V1, M92-V3, M5-V8 and M5-V28 respectively, in good agreement with previous determinations of cluster mean velocities.(c) Astronomical Society of the Pacificc Astronomical Society of the Pacificc Astronomical Society of the Pacifi.
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