Open AccessThe IRAS PSC z dipole
Author(s) -
RowanRobinson M.,
Sharpe J.,
Oliver S. J.,
Keeble O.,
Canavezes A.,
Saunders W.,
Taylor A. N.,
Valentine H.,
Frenk C. S.,
Efstathiou G. P.,
McMahon R. G.,
White S. D. M.,
Sutherland W.,
Tadros H.,
Maddox S.
Publication year - 2000
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.1365-8711.2000.03313.x
Subject(s) - physics , cosmic microwave background , astrophysics , dipole , redshift , galaxy , sky , amplitude , spherical harmonics , cosmic background radiation , astronomy , anisotropy , optics , quantum mechanics
We use the PSC z IRAS galaxy redshift survey to analyse the cosmological galaxy dipole out to a distance of 300 h −1 Mpc. The masked area is filled in three different ways, first by sampling the whole sky at random, secondly by using neighbouring areas to fill a masked region, and thirdly using a spherical harmonic analysis. The method of treatment of the mask is found to have a significant effect on the final calculated dipole. The conversion from redshift space to real space is accomplished by using an analytical model of the cluster and void distribution, based on 88 nearby groups, 854 clusters and 163 voids, with some of the clusters and all of the voids found from the PSC z data base. The dipole for the whole PSC z sample appears to have converged within a distance of 200 h −1 Mpc and yields a value for , consistent with earlier determinations from IRAS samples by a variety of methods. For b =1, the 2 σ range for Ω 0 is 0.43–1.02. The direction of the dipole is within 13° of the cosmic microwave background (CMB) dipole, the main uncertainty in direction being associated with the masked area behind the Galactic plane. The improbability of further major contributions to the dipole amplitude coming from volumes larger than those surveyed here means that the question of the origin of the CMB dipole is essentially resolved.