[PLO2001] J1604+4304 2537 , the SIMBAD biblio

2001AJ....122.1125P - Astron. J., 122, 1125-1150 (2001/September-0)

A study of nine high-redshift clusters of galaxies. IV. Photometry and spectra of clusters 1324+3011 and 1604+4321.

POSTMAN M., LUBIN L.M. and OKE J.B.

Abstract (from CDS):

New photometric and spectroscopic observations of galaxies in the directions of three distant clusters are presented as part of our ongoing high-redshift cluster survey. The clusters are Cl 1324+3011 at z=0.76, Cl 1604+4304 at z=0.90, and Cl 1604+4321 at z=0.92. We have spectroscopically confirmed cluster membership for 20-40 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 770 h–165 kpc of each cluster are in excess of 8x1014 h–165 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 [O II] is greater than 15 Å, the fraction of active cluster galaxies within the central 1.0 h–165 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 1 h–165 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 and 2.5 h–165 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 fitted 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 (BCGs) in these clusters. The BCGs are typically twice as luminous as their current epoch counterparts.

Abstract Copyright:

Journal keyword(s): Cosmology: Observations - Galaxies: Clusters: General

VizieR on-line data: <Available at CDS (J/AJ/122/1125): table2.dat table3.dat table4.dat>

Nomenclature: Table 2: [PLO2001] J1324+3011 NNNN N=161 among 4952. Table 3: [PLO2001] J1604+4304 NNNN N=109 among 3505. Table 4: [PLO2001] J1604+4321 NNNN N=163 among 6322.

CDS comments: There are more objects in the electronic files than in the published tables.

Simbad objects: 496

goto View the references in ADS