REDSHIFTS AND OPTICAL-PROPERTIES FOR A STATISTICALLY COMPLETE SAMPLE OF POOR GALAXY CLUSTERS

From the poor cluster catalog of White ct al. (1996), we define a samp le of 71 optically-selected poor galaxy clusters. The surface-density enhancement we require for our clusters falls between that of the loos e associations of Turner & Gott [AJ, 91, 204 (1976)] and the Hickson c ompact groups [Hickson, ApJ, 255, 382 (1982)]. We review the selection biases and determine the statistical completeness of the sample. For this sample, we report new velocity measurements made with the ARC 3.5 -m Dual-Imaging spectrograph and the 2.3-m Steward Observatory MX fibe r spectrograph. Combining our own measurements with those from the lit erature, we examine the velocity distributions, velocity dispersions, and 1D velocity substructure for our poor cluster sample, and compare our results to other poor cluster samples. We find that approximately half of the sample may have significant 1D velocity substructure. The optical morphology, large-scale environment, and velocity field of man y of these clusters are indicative of young, dynamically evolving syst ems. In future papers, we will use this sample to derive the poor clus ter x-ray luminosity function and gas mass function, and will examine the optical/x-ray properties of the clusters in more detail. (C) 1996 American Astronomical Society.