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HD 90249


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The KPNO/Deeprange Distant Cluster Survey. I. The Catalog and the Space Density of Intermediate-Redshift Clusters
We have conducted an automated search for galaxy clusters within acontiguous 16 deg2 I-band survey in the north Galactichemisphere. A matched filter detection algorithm identifies 444 clustercandidates in the range 0.2<~z<~1.2. The full catalog is presentedalong with the results from a follow-up spectroscopic survey. Theestimated redshift distribution of the cluster candidates is consistentwith a constant comoving density over the range0.2<=zest<=0.8. A decline in the cluster space densityby more than a factor of 3 over this redshift range is rejected at thegreater than 99.9% confidence level. We find that the space density ofΛcl>=40 clusters in our survey lies in the range(1.6-1.8)×10-5 h375Mpc-3, ~1.5 times higher than the local distribution ofcomparably rich Abell richness class >=0 clusters. TheΛcl distribution is consistent with a power law. Thediscrepancy between the space density of Abell clusters and the clustersin this survey declines quickly as Λcl increases,suggesting that the difference at lower richness is due to significantincompleteness in the Abell catalog. A percolation analysis reveals that10%-20% of the spectroscopically confirmed distant clusters are linkedinto superclusters at overdensities between10<δρ/ρ<50, similar to what is seen in the localcluster distribution. This suggests that there has been little evolutionof the cluster-cluster correlation length for z<~0.5.

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Osservazione e dati astrometrici

Costellazione:Orsa Maggiore
Ascensione retta:10h26m22.82s
Declinazione:+54°24'26.9"
Magnitudine apparente:6.994
Distanza:184.162 parsec
Moto proprio RA:-46.8
Moto proprio Dec:0.1
B-T magnitude:8.095
V-T magnitude:7.085

Cataloghi e designazioni:
Nomi esatti   (Edit)
HD 1989HD 90249
TYCHO-2 2000TYC 3816-741-1
USNO-A2.0USNO-A2 1425-07495601
HIPHIP 51097

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