Baryon acoustic oscillations from the SDSS DR10 galaxies angular correlation function

Abstract

The 2-point angular correlation function w(θ) (2PACF), where θ is the angular separation between pairs of galaxies, provides the transversal Baryon Acoustic Oscillation (BAO) signal almost model-independently. In this paper we use 409,337 luminous red galaxies in the redshift range z = [0.440, 0.555] obtained from the tenth data release of the Sloan Digital Sky Survey (SDSS DR10) to estimate θBAO(z) from the 2PACF at six redshift shells. Since noise and systematics can hide the BAO signature in the w − θ plane, we also discuss some criteria to localize the acoustic bump. We identify two sources of model-dependence in the analysis, namely, the value of the acoustic scale from Cosmic Microwave Background (CMB) measurements and the correction in the θBAO(z) position due to projection effects. Constraints on the dark energy equation-of-state parameter w(z) from the θBAO(z) diagram are derived, as well as from a joint analysis with current CMB measurements. We find that the standard ΛCDM model as well as some of its extensions are in good agreement with these θBAO(z) measurements. * Electronic address: gabriela@on.br † Electronic address: bernui@on.br ‡ Electronic address: micolbenetti@on.br § Electronic address: jcarvalho@on.br ¶ Electronic address: alcaniz@on.br 1 The acoustic scale is defined as rs = ∞ z d cs(z) H(z) dz, where z d ≈ 1070 is the redshift of the drag epoch and cs(z) is the sound speed of the photon-baryon fluid. arXiv:1507.08972v2 [astro-ph.CO]

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Null test for interactions in the dark sector

“…where we have used equation (28). Note that, thanks to the linearity in the parameters, the best fits {c α,bf } were not used and this computation is exact rather than only valid at the first order in a Taylor expansion.…”

An estimate of the dark matter density from galaxy clusters and supernovae data

“…[10][11][12][13][14][15]). This scenario makes clear that model-independent measurements of cosmological quantities, which is a challenge for observational cosmology, are of fundamental importance for a proper evaluation of the possibilities (see [16,17] for a discussion). Among these possibilities, * Electronic address: holandarfl@fisica.ufrn.br † Electronic address: rsousa@on.br ‡ Electronic address: javierernesto@on.br § Electronic address: alcaniz@on.br 1 Another possibility is that the matter content of the universe is subject to dissipative processes (see e.g.…”