Open AccessCluster correlations in redshift space
Author(s) -
Padilla N.D.,
Baugh C.M.
Publication year - 2002
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1046/j.1365-8711.2002.04992.x
Subject(s) - physics , redshift , astrophysics , spectral density , hubble's law , galaxy , cluster (spacecraft) , redshift space distortions , cold dark matter , galaxy cluster , dark matter , dark energy , peculiar velocity , radius , correlation function (quantum field theory) , hubble volume , statistical physics , redshift survey , cosmology , statistics , quantum mechanics , mathematics , computer security , computer science , dielectric , programming language
We test an analytic model for the two‐point correlations of galaxy clusters in redshift space using the Hubble volume N ‐body simulations. The correlation function of clusters shows no enhancement along the line of sight, owing to the lack of any virialized structures in the cluster distribution. However, the distortion of the clustering pattern arising from coherent bulk motions is clearly visible. The distribution of cluster peculiar motions is well described by a Gaussian, except in the extreme high‐velocity tails. The simulations produce a small but significant number of clusters with large peculiar motions. The form of the redshift‐space power spectrum is strongly influenced by errors in measured cluster redshifts in extant surveys. When these errors are taken into account, the model reproduces the power spectrum recovered from the simulation to an accuracy of 15 per cent or better over a decade in wavenumber. We compare our analytic predictions with the power spectrum measured from the APM cluster redshift survey. The cluster power spectrum constrains the amplitude of density fluctuations, as measured by the linear rms variance in spheres of radius 8 h −1 Mpc, denoted by σ 8 . When combined with the constraints on σ 8 and the density parameter Ω derived from the local abundance of clusters, we find a best‐fitting cold dark matter model with and , for a power spectrum shape that matches that measured for galaxies. However, for the best‐fitting value of Ω and given the value of Hubble's constant from recent measurements, the assumed shape of the power spectrum is incompatible with the most readily motivated predictions from the cold dark matter paradigm.