WEAK GRAVITATIONAL LENSING BY A SAMPLE OF X-RAY-LUMINOUS CLUSTERS OF GALAXIES. Ⅱ. COMPARISON WITH VIRIAL MASSES

摘要

Dynamic velocity dispersion and mass estimates are given for a sample of five X-ray-luminous rich clusters of galaxies at intermediate redshifts (z ～ 0.3) drawn from a sample of 39 clusters for which we have obtained gravitational lens mass estimates. The velocity dispersions are determined from between nine and 20 redshifts measured with the low-dispersion survey spectrograph (LDSS) of the William Herschel Telescope, and virial radii are determined from imaging using the UH8K mosaic CCD camera on the University of Hawaii 2.24 m telescope. Including clusters with velocity dispersions taken from the literature, we have velocity dispersion estimates for 12 clusters in our gravitational lensing sample. For this sample we compare the dynamic velocity dispersion estimates with our estimates of the velocity dispersions made from gravitational lensing by fitting a singular isothermal sphere profile to the observed tangential weak lensing distortion as a function of radius. In all but two clusters, we find a good agreement between the velocity dispersion estimates based on spectroscopy and those based on weak lensing.