Cosmological Constraints from the Clustering of the Sloan Digital Sky Survey DR7 Luminous Red Galaxies - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We present the power spectrum of the reconstructed halo density field derivedfrom a sample of Luminous Red Galaxies LRGs from the Sloan Digital Sky SurveySeventh Data Release DR7. The halo power spectrum has a direct connection tothe underlying dark matter power for k <= 0.2 h-Mpc, well into the quasi-linearregime. This enables us to use a factor of ~8 more modes in the cosmologicalanalysis than an analysis with kmax = 0.1 h-Mpc, as was adopted in the SDSSteam analysis of the DR4 LRG sample Tegmark et al. 2006. The observed halopower spectrum for 0.02 < k < 0.2 h-Mpc is well-fit by our model: chi^2 = 39.6for 40 degrees of freedom for the best fit LCDM model. We find \Omega m h^2 *n s-0.96^0.13 = 0.141^{+0.009} {-0.012} for a power law primordial powerspectrum with spectral index n s and \Omega b h^2 = 0.02265 fixed, consistentwith CMB measurements. The halo power spectrum also constrains the ratio of thecomoving sound horizon at the baryon-drag epoch to an effective distance toz=0.35: r s-D V0.35 = 0.1097^{+0.0039} {-0.0042}. Combining the halo powerspectrum measurement with the WMAP 5 year results, for the flat LCDM model wefind \Omega m = 0.289 +- 0.019 and H 0 = 69.4 +- 1.6 km-s-Mpc. Allowing formassive neutrinos in LCDM, we find \sum m { u} < 0.62 eV at the 95% confidencelevel. If we instead consider the effective number of relativistic species Neffas a free parameter, we find Neff = 4.8^{+1.8} {-1.7}. Combining also with theKowalski et al. 2008 supernova sample, we find \Omega {tot} = 1.011 +- 0.009and w = -0.99 +- 0.11 for an open cosmology with constant dark energy equationof state w.



Autor: Beth A. Reid, Will J. Percival, Daniel J. Eisenstein, Licia Verde, David N. Spergel, Ramin A. Skibba, Neta A. Bahcall, Tamas Buda

Fuente: https://arxiv.org/







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