Space Velocities of Southern Globular Clusters. II. New Results for 10 Clusters

Abstract

Absolute proper motions have been measured for 10 clusters, in addition to the sample of five clusters presented in an earlier paper. These newly measured clusters are NGC 1904 (M79), NGC 2298, NGC 4590 (M68), NGC 5139 (ω Cen), NGC 5897, NGC 6093 (M80), NGC 6121 (M4), NGC 6144, NGC 6809 (M55), and NGC 7099 (M30). The correction to absolute proper motion is determined based on galaxies, except for one field with high extinction, for which we used the Hipparcos system. This latter correction proves to be very useful for fields at low Galactic latitude, provided magnitude-dependent systematics are well controlled. The errors in absolute proper motion per cluster range between 0.4 and 1.0 mas yr-1. Space velocities are also determined, and the kinematics are briefly discussed; a companion paper will present a detailed analysis of orbits in conjunction with other physical parameters of clusters.