NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-22 T17:52:59 PDT
Help | Comment | NED Home

For refcode 1996ApJ...462...32C:
Retrieve 16 NED objects in this reference.
Please click here for ADS abstract

NED Abstract

Copyright by American Astronomical Society. Reproduced by permission
1996ApJ...462...32C GALAXY CLUSTER VIRIAL MASSES AND {OMEGA} R. G. CARLBERG, H. K. C. YEE, E. ELLINGSON, R. ABRAHAM, P. GRAVEL, S. MORRIS, AND C. J. PRITCHET Received 1995 September 6; accepted 1995 October 6 ABSTRACT The mean density of the universe is equal to the mass of a large galaxy cluster divided by the equivalent comoving volume in the field from which that mass originated. To reexamine the rich cluster {OMEGA}- value the CNOC Cluster Survey has observed 16 high X-ray luminosity clusters in the redshift range 0.17-0.55, obtaining approximately 2600 velocities in their fields. The systemic redshift, the rms line-of-sight velocity dispersion {sigma}_1_, and the mean harmonic radius r_{nu}_ are derived for each cluster using algorithms that correct for interlopers in redshift space and measure the angular extent of the sampling. The virial mass, and its internal error, are derived from {sigma}_1_ and r_{nu}_. The cluster luminosity is estimated from the K-corrected r-band luminosities of the cluster galaxies. Directly adding all the light to M_r_^K^ = - 18.5 mag, about 0.2L_sun_, and extrapolating for the small amount of light below the limit, the average mass-to-light ratio of the clusters is 295 +/- 53 h M_sun_ L_sun_^-1^, and the average mass per galaxy to M_r_^K^ = - 19.0 mag is 4.2 +/- 1.1 x 10^12^ h^-1^ M_sun_. The clusters are consistent with having a universal M_{nu}_/L-value (within the errors of about 25%) independent of their velocity dispersion, mean color of their galaxies, blue galaxy content, redshift, or mean interior density. Using field galaxies within the same data set, with the same corrections, we find that the closure mass-to-light ratio, {rho}_c_/j, is 1025 +/- 140 h M_sun_ L_sun_^-1^, and the closure mass per galaxy to M_r_^K^ = - 19.0 mag, {rho}_c_/{PHI} is 15.5 +/- 3.0 x 10^12^ h^-1^ M_sun_. Under the assumptions that the galaxies are distributed like the mass and that the galaxy luminosities and numbers are statistically conserved, assumptions that these data indirectly support, {OMEGA}_0_ = 0.24 +/- 0.05 +/- 0.09, where the errors are, respectively, the 1 {sigma} random error and an estimate of the possible systematic error resulting from the normalization to galaxy content. Subject headings: cosmology: observations - galaxies: clusters: general galaxies: fundamental parameters
Retrieve 16 NED objects in this reference.
Please click here for ADS abstract

Back to NED Home