A Study of Nine High - Redshift Clusters of Galaxies : IV . Photometry and Spectra of Clusters 1324 + 3011 and 1604 + 4321 Marc Postman

New photometric and spectroscopic observations of galaxies in the directions of three distant clusters are presented as part of our on-going high-redshift cluster survey. The clusters are CL1324+3011 at z = 0.76, CL1604+4304 at z = 0.90, and CL1604+4321 at z = 0.92. We have spectroscopically confirmed cluster membership for 20 to 40 galaxies in each system and have also obtained spectra for over 280 field galaxies spanning the range 0 < z < 2.5. Kinematic estimates of the mass within the central 770h 65 kpc of each cluster are in excess of 8×10 14 h 65 M⊙. The observed x-ray luminosities in these clusters are at least a factor of 3 smaller than those observed in clusters with similar velocity dispersions at z ≤ 0.4. These clusters contain a significant population of elliptical-like galaxies, although these galaxies are not nearly as dominant as in massive clusters at z ≤ 0.5. We also find a large population of blue cluster members. Defining an active galaxy as one in which the rest equivalent width of [OII] is greater than 15Å, the fraction of active cluster galaxies, within the central 1.0 h 65 Mpc, is 45%. In the field population, we find that 65% of the galaxies with redshifts between z = 0.40 and z = 0.85 are active, while the fraction is 79% for field galaxies at z > 0.85. The star formation rate normalized by the rest AB B−band magnitude, SFRN, increases as the redshift increases at a given evolving luminosity. At a given redshift, however, SFRN decreases linearly with increasing luminosity indicating a remarkable insensitivity of the star formation rate to the intrinsic luminosity of the galaxy over the range −18 ≥ ABB ≥ −22. Cluster galaxies in the central 1h 65 Mpc regions exhibit depressed star formation rates and contain a larger fraction of galaxies with “k” type spectra. The star formation rates in galaxies lying between 1 − 2.5h 65 Mpc from the cluster centers, however, are in good agreement with that in galaxies in the general field at similar redshifts. The spectroscopic and photometric properties of the cluster galaxies are well fit by Bruzual-Charlot solar metallicity, constant-age (4.8 Gyr at z = 0.9), variable tau models. Metallicities in these clusters must be at least 0.2 of solar, and a significant amount of dust extinction is unlikely. We are able to measure significant evolution in the B-band luminosity function over the range 0.1 ≤ z ≤ 1. The characteristic luminosity increases by a factor of 3 with increasing redshift over this range. This result is consistent with an analysis of the luminosities of the brightest cluster galaxies in these clusters. The BCGs are typically twice as luminous as their current epoch counterparts. Subject headings: galaxies: clusters: general – cosmology: observations