The 2dF QSO Redshift Survey XV. Correlation analysis of redshiftspace distortions
Abstract
We analyse the redshiftspace (zspace) distortions of quasistellar object (QSO) clustering in the 2degree field instrument (2dF) QSO Redshift Survey (2QZ). To interpret the zspace correlation function, ξ(σ, π), we require an accurate model for the QSO realspace correlation function, ξ(r). Although a single powerlaw ξ(r) ~r^{γ} model fits the projected correlation function [w_{p}(σ)] at small scales, it implies somewhat too shallow a slope for both w_{p}(σ) and the zspace correlation function, ξ(s), at larger scales (>~20h^{1}Mpc). Motivated by the form for ξ(r) seen in the 2dF Galaxy Redshift Survey (2dFGRS) and in standard Λ cold dark matter (CDM) predictions, we use a double powerlaw model for ξ(r), which gives a good fit to ξ(s) and w_{p}(σ). The model is parametrized by a slope of γ= 1.45 for 1 < r < 10h^{1}Mpc and γ= 2.30 for 10 < r < 40h^{1}Mpc. As found for the 2dFGRS, the value of β determined from the ratio of ξ(s)/ξ(r) depends sensitively on the form of ξ(r) assumed. With our double powerlaw form for ξ(r), we measure β(z= 1.4) = 0.32^{+0.09}_{0.11}. Assuming the same model for ξ(r), we then analyse the zspace distortions in the 2QZ ξ(σ, π) and put constraints on the values of Ω^{0}_{m} and β(z= 1.4), using an improved version of the method of Hoyle et al. The constraints we derive are Ω^{0}_{m}= 0.35^{+0.19}_{0.13}, β(z= 1.4) = 0.50^{+0.13}_{0.15}, in agreement with our ξ(s)/ξ(r) results at the ~1σ level.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 July 2005
 DOI:
 10.1111/j.13652966.2005.09094.x
 arXiv:
 arXiv:astroph/0504438
 Bibcode:
 2005MNRAS.360.1040D
 Keywords:

 surveys;
 quasars: general;
 cosmology: observations;
 largescale structure of Universe;
 Astrophysics
 EPrint:
 Accepted for publication in MNRAS. 17 pages, 15 figures