TY - JOUR
T1 - Angular correlations in decontaminated abell catalogs
AU - Olivier, Scot
AU - Blumenthal, George R.
AU - Dekel, Avishai
AU - Primack, Joel R.
AU - Stanhill, David
PY - 1990/6/10
Y1 - 1990/6/10
N2 - We study the effect of projection contamination on the angular autocorrelation function wcc(θ) in the Abell northern and Abell-Corwin-Olowin southern catalogs of rich clusters of galaxies. We do this by constructing a "decontaminated" catalog of richness R ≥ 1, distance D = 5, 6 clusters, using a robust model in which the galaxy number density is a superposition of a uniform field plus spherical halos centered on each cluster. The halo profile functions are derived from observed cluster-galaxy correlation functions, ζcg(r). This procedure eliminates 9%-14% of the 2004 clusters in the two catalogs, depending on the ζcg used. At small angles, θ < 1°, decontamination reduces the amplitude of wcc by a factor of 2 or more, and the large (Poisson) errors indicate that wcc is positive only at the 2 σ level; thus it cannot provide useful constraints on theory. In the range 1° ≤ θ ≤ 3°, however, wcc has a zone of statistical significance. Its amplitude there is reduced by decontamination only by ∼30% or less, and it is positive at the 5 σ level both in the north and the south, indicating spatial correlations on scales of order 10-30h-1 Mpc. In this zone the results are insensitive to the use of local versus global cluster background normalization in calculating wcc. On large angles, θ > 3°, the effect of decontamination is negligible. On these scales the north and the south differ significantly; while in the south wcc is consistent with zero at the 2 σ level, it stays significantly positive in the north out to 40°. This inconsistency and other problems with the northern sample argue against drawing any conclusions from the results beyond 3°. The wcc(θ) of the decontaminated D = 5, 6 sample for θ < 3° is consistent with our previous results on the ζcc(r) of the decontaminated D ≤ 4 redshift sample to within 2 σ, roughly consistent with the expected scaling with depth. The data in the 1°-3° zone is in significant conflict with the predictions of the "standard" cold dark matter model; the discrepancy is ∼5 σ with Poisson errors, and ∼3.5 σ when the error bars are corrected to include clustering. In this zone, wcc is consistent with other models such as the hybrid model of CDM and baryons in an open universe, while the "explosion scenario" somewhat overestimates the cluster correlations.
AB - We study the effect of projection contamination on the angular autocorrelation function wcc(θ) in the Abell northern and Abell-Corwin-Olowin southern catalogs of rich clusters of galaxies. We do this by constructing a "decontaminated" catalog of richness R ≥ 1, distance D = 5, 6 clusters, using a robust model in which the galaxy number density is a superposition of a uniform field plus spherical halos centered on each cluster. The halo profile functions are derived from observed cluster-galaxy correlation functions, ζcg(r). This procedure eliminates 9%-14% of the 2004 clusters in the two catalogs, depending on the ζcg used. At small angles, θ < 1°, decontamination reduces the amplitude of wcc by a factor of 2 or more, and the large (Poisson) errors indicate that wcc is positive only at the 2 σ level; thus it cannot provide useful constraints on theory. In the range 1° ≤ θ ≤ 3°, however, wcc has a zone of statistical significance. Its amplitude there is reduced by decontamination only by ∼30% or less, and it is positive at the 5 σ level both in the north and the south, indicating spatial correlations on scales of order 10-30h-1 Mpc. In this zone the results are insensitive to the use of local versus global cluster background normalization in calculating wcc. On large angles, θ > 3°, the effect of decontamination is negligible. On these scales the north and the south differ significantly; while in the south wcc is consistent with zero at the 2 σ level, it stays significantly positive in the north out to 40°. This inconsistency and other problems with the northern sample argue against drawing any conclusions from the results beyond 3°. The wcc(θ) of the decontaminated D = 5, 6 sample for θ < 3° is consistent with our previous results on the ζcc(r) of the decontaminated D ≤ 4 redshift sample to within 2 σ, roughly consistent with the expected scaling with depth. The data in the 1°-3° zone is in significant conflict with the predictions of the "standard" cold dark matter model; the discrepancy is ∼5 σ with Poisson errors, and ∼3.5 σ when the error bars are corrected to include clustering. In this zone, wcc is consistent with other models such as the hybrid model of CDM and baryons in an open universe, while the "explosion scenario" somewhat overestimates the cluster correlations.
KW - Cosmology
KW - Galaxies: clustering
UR - http://www.scopus.com/inward/record.url?scp=0011410793&partnerID=8YFLogxK
U2 - 10.1086/168809
DO - 10.1086/168809
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AN - SCOPUS:0011410793
SN - 0004-637X
VL - 356
SP - 1
EP - 13
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
ER -