Large-scale galaxy correlations as a test for dark energy

¹ LATT, 14 avenue Édouard Belin, 31400 Toulouse, France e-mail: alain.blanchard@ast.obs-mip.fr
² LATT, 14 avenue Édouard Belin, 31400 Toulouse, France e-mail: douspis@ast.obs-mip.fr
³ Astrophysics Group, Imperial College, Blackett Laboratory, Prince Consort Road, London SW7 2BW, UK
⁴ Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, UK e-mail: sarkar@thphys.ox.ac.uk

Received: 5 December 2005
Accepted: 30 December 2005

Abstract

We have shown earlier that, contrary to popular belief, Einstein-de Sitter (E-deS) models can still fit the WMAP data on the cosmic microwave background provided one adopts a low Hubble constant and relaxes the usual assumption that the primordial density perturbation is scale-free. The recent SDSS measurement of the large-scale correlation function of luminous red galaxies at has however provided a new constraint by detecting a “baryon acoustic peak”. Our best-fit E-deS models do possess a baryonic feature at a similar physical scale as the best-fit ΛCDM concordance model, but do not fit the new observations as well as the latter. In particular the shape of the correlation function in the range ~ Mpc cannot be reproduced properly without violating the CMB angular power spectrum in the multipole range . Thus, the combination of the CMB fluctuations and the shape of the correlation function up to ~ Mpc, if confirmed, does seem to require dark energy for a homogeneous cosmological model based on (adiabatic) inflationary perturbations.