An analysis of R ≥ 1 Abell clusters is presented for samples containing recent redshifts from the MX Northern Abell Cluster Survey. The newly obtained redshifts from the MX Survey as well as those from the ESO Nearby Abell Cluster Survey (ENACS) provide the necessary data for the studied Abell cluster datasets is not present in our samples. There are, however, indications of residual anisotropies which we show are the result of two elongated superclusters, Ursa Majoris and Corona Borealis whose axes lie near the line-of-sight. After rotating these superclusters so that their semi-major axes are perpendicular to the line-of-sight, we find no indication of anisotropy in ξ(σ, π). The amplitude and slope of the correlation function remain the same before and after these rotations. We also remove a subset of R = 1 Abell/ACO clusters that show sizeable foreground/background galaxy contamination and again find no change in the amplitude or slope of the correlation function. We conclude that the correlation length of R ≥ 1 Abell clusters is not artificially enhanced by line-of-sight anisotropies.

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We present a joint analysis of the power spectra of density fluctuations from three independent cosmological redshift surveys; the PSCz galaxy catalog, the APM galaxy cluster catalog and the Abell/ACO cluster catalog. Over the range 0.03 ≤ k ≤ 0.15hMpc −1 , the amplitudes of these three power spectra are related through a simple linear biasing model with b = 1.5 and b = 3.6 for Abell/ACO versus APM and Abell/ACO versus the PSCz respectively. Furthermore, the shape of these power spectra are remarkably similar despite the fact that they are comprised of significantly different objects (individual galaxies through to rich clusters). Individually, each of these surveys show visible evidence for "valleys" in their power spectra i.e. departures from a smooth featureless spectrum-at similar wavenumbers. We use a newly developed statistical technique called the False Discovery Rate, to show that these "valleys" are statistically significant. One favored cosmological explanation for such features in the power spectrum is the presence of a non-negligible baryon fraction (Ω b) in the Universe which causes acoustic oscillations in the transfer function of adiabatic inflationary models. We have performed a maximum-likelihood marginalization over four important cosmological parameters of this model (Ω m , Ω b , n s , H o). We use a prior on H 0 = 69 ± 15, and find Ω m h 2 = 0.12 +0.03 −0.02 , Ω b h 2 = 0.029 +0.011 −0.015 , n s = 1.08 +0.17 −0.20 (2σ confidence limits) which are fully consistent with the favored values of these cosmological parameters from the recent Cosmic Microwave Background (CMB) experiments. This agreement strongly suggests that we have detected baryonic oscillations in the power spectrum of matter at a level expected from a Cold Dark Matter (CDM) model normalized to fit these CMB measurements.

Recently, there have been numerous analyses of the redshift space power spectrum of rich clusters of galaxies. Some of these analyses indicate a "bump" in the Abell/ACO cluster power spectrum around k = 0.05hMpc −1 . Such a feature in the power spectrum excludes most standard formation models and indicates possible periodicity in the distribution of large-scale structure. However, the data used in detecting this peak include clusters with estimated redshifts and/or clusters outside of Abell's (1958) statistical sample, i.e. R = 0 clusters. Here, we present estimates of the redshift-space power spectrum for a newly expanded sample of 637 R ≥ 1 Abell/ACO clusters which has a constant number density to z = 0.10 in the Southern Hemisphere and a nearly constant number density to z = 0.14 in the Northern Hemisphere. The volume sampled, ∼ 10 8 h −3 Mpc 3 , is large enough to accurately calculate the power per mode to scales approaching 10 3 h −1 Mpc. We find the shape of the power spectrum is a power-law on scales 0.02 ≤ k ≤ 0.10hMpc −1 , with enhanced power over less rare clusters such as APM clusters. The power-law here follows n = −1.4. The power spectrum is essentially featureless, although we do see a dip near k = 0.04hMpc −1 which cannot be considered statistically significant based on this data alone. We do not detect a narrow peak at k ∼ 0.05hMpc −1 and there is no evidence for a turn-over in the power spectrum as has been previously reported. We compare the shape of the Abell/ACO rich cluster power spectrum to various linear models.

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