"A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey"

Details "A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey" "A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey"

Dec 2001

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001stin...0217266j&link_type=abstract

Technical Report, Smithsonian Astrophysical Observatory Cambridge, MA United States

Astronomy and Astrophysics

Astrophysics

X Rays, Cluster Analysis, Surface Properties, Galaxies, Flux Density, Emission, Luminosity, Populations, Proportional Counters, Red Shift, Rosat Mission, Sensitivity

Scientific paper

We have measured the surface density of galaxies toward 14 X-ray-selected cluster candidates at redshifts zi 0.46, and we show that they are associated with rich galaxy concentrations. These clusters, having X-ray luminosities of Lx(0.5-2 keV) approx. (0.5 - 2.6) x 1044 ergs/ sec are among the most distant and luminous in our 160 deg2 ROSAT Position Sensitive Proportional Counter cluster survey. We find that the clusters range between Abell richness classes 0 and 2 and have a most probable richness class of 1. We compare the richness distribution of our distant clusters to those for three samples of nearby clusters with similar X-ray luminosities. We find that the nearby and distant samples have similar richness distributions, which shows that clusters have apparently not evolved substantially in richness since redshift z=0.5. There is, however, a marginal tendency for the distant clusters to be slightly poorer than nearby clusters, although deeper multicolor data for a large sample would be required to confirm this trend. We compare the distribution of distant X-ray clusters in the LX-richness plane to the distribution of optically selected clusters from the Palomar Distant Cluster Survey. The optically selected clusters appear overly rich for their X-ray luminosities, when compared to X-ray-selected clusters. Apparently, X-ray and optical surveys do not necessarily sample identical mass concentrations at large redshifts. This may indicate the existence of a population of optically rich clusters with anomalously low X-ray emission, More likely, however, it reflects the tendency for optical surveys to select unvirialized mass concentrations, as might be expected when peering along large-scale filaments.

Affiliated with

Also associated with

No associations

Rating

"A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey" does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with "A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey", we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and "A Richness Study of 14 Distant X-Ray Clusters from the 160 Square Degree Survey" will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1375810