Open AccessThe 2dF QSO Redshift Survey – XIII. A measurement of Λ from the quasi‐stellar object power spectrum, P S ( k ∥ , k ⊥ )
Author(s) -
Outram P. J.,
Shanks T.,
Boyle B. J.,
Croom S. M.,
Hoyle Fiona,
Loaring N. S.,
Miller L.,
Smith R. J.
Publication year - 2004
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 - 10.1111/j.1365-2966.2004.07348.x
Subject(s) - physics , redshift , astrophysics , cosmology , redshift survey , galaxy
We report on measurements of the cosmological constant, Λ, and the redshift space distortion parameter β=Ω 0.6 m / b , based on an analysis of the quasi‐stellar object (QSO) power spectrum parallel and perpendicular to the observer's line of sight, P S ( k ∥ , k ⊥ ) , from the final catalogue of the Two‐Degree Field (2dF) QSO Redshift Survey. We derive a joint Λ−β constraint from the geometric and redshift‐space distortions in the power spectrum. By combining this result with a second constraint based on mass clustering evolution, we break this degeneracy and obtain strong constraints on both parameters. Assuming a flat (Ω m +Ω Λ = 1) cosmology and a Λ cosmology r ( z ) function to convert from redshift into comoving distance, we find best‐fitting values of Ω Λ = 0.71 +0.09 −0.17 and β q ( z ∼ 1.4) = 0.45 +0.09 −0.11 . Assuming instead an Einstein–de Sitter cosmology r ( z ) we find that the best‐fitting model obtained, with Ω Λ = 0.64 +0.11 −0.16 and β q ( z ∼ 1.4) = 0.40 +0.09 −0.09 , is consistent with the Λ r ( z ) results, and inconsistent with a Ω Λ = 0 flat cosmology at over 95 per cent confidence.