paper

The Power Spectrum of Rich Clusters of Galaxies on Large Spatial Scales

arXiv:astro-ph/9708259 · doi:10.1046/j.1365-8711.1998.01441.x

Abstract

We present an analysis of the redshift-space power spectrum, , of rich clusters of galaxies based on an automated cluster catalogue selected from the APM Galaxy Survey. We find that can be approximated by a power law, $P(k)\proptok^{n}$, with over the wavenumber range $0.04\hr<k<0.1\hr$. Over this range of wavenumbers, the APM cluster power spectrum has the same shape as the power spectra measured for optical and IRAS galaxies. This is consistent with a simple linear bias model in which different tracers have the same power spectrum as that of the mass distribution but shifted in amplitude by a constant biasing factor. On larger scales, the power spectrum of APM clusters flattens and appears to turn over on a scale $k \sim 0.03\hmpcrev$. We compare the power spectra estimated from simulated APM cluster catalogues to those estimated directly from cubical N-body simulation volumes and find that the APM cluster survey should give reliable estimates of the true power spectrum at wavenumbers $k \simgt 0.02\hmpcrev$. These results suggest that the observed turn-over in the power spectrum may be a real feature of the cluster distribution and that we have detected the transition to a near scale-invariant power spectrum implied by observations of anisotropies in the cosmic microwave background radiation. The scale of the turn-over in the cluster power spectrum is in good agreement with the scale of the turn-over observed in the power spectrum of APM galaxies.

9 pages, 7 ps figures, two style files, submitted to MNRAS. Un-xxx-ed version available at http://www-astro.physics.ox.ac.uk/research/preprints/aug97/cluspaper.ps.gz

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