Cosmological constraints from the SDSS luminous red galaxies

Abstract

We measure the large-scale real-space power spectrum P (k) using luminous red galaxies (LRGs) in the Sloan Digital Sky Survey (SDSS) and use this measurement to sharpen constraints on cosmological parameters from the Wilkinson Microwave Anisotropy Probe (WMAP). We employ a matrix-based power spectrum estimation method using Pseudo-Karhunen-Loève eigenmodes, producing uncorrelated minimum-variance measurements in 20 k-bands of both the clustering power and its anisotropy due to redshift-space distortions, with narrow and well-behaved window functions in the range 0.01 h/Mpc < k < 0.2 h/Mpc. Results from the LRG and main galaxy samples are consistent, with the former providing higher signal-to-noise. Our results are robust to omitting angular and radial density fluctuations and are consistent between different parts of the sky. They provide a striking confirmation of the predicted large-scale ΛCDM power spectrum. Combining only SDSS LRG and WMAP data places robust constraints on many cosmological parameters that complement prior analyses of multiple data sets. The LRGs provide independent cross-checks on Ωm and the baryon fraction in good agreement with WMAP. Within the context of flat ΛCDM models, our LRG measurements complement WMAP by sharpening the constraints on the matter density, the neutrino density and the tensor amplitude by about a factor of two, giving Ωm = 0.24±0.02 (1σ), mν ∼ < 0.9 eV (95%) and r < 0.3 (95%). Baryon oscillations are clearly detected and provide a robust measurement of the comoving distance to the median survey redshift z = 0.35 independent of curvature and dark energy properties. Within the ΛCDM framework, our power spectrum measurement improves the evidence for spatial flatness, sharpening the curvature constraint Ωtot = 1.05±0.05 from WMAP alone to Ωtot = 1.003 ± 0.010. Assuming Ωtot = 1, the equation of state parameter is constrained to w = −0.94 ± 0.09, indicating the potential for more ambitious future LRG measurements to provide precision tests of the nature of dark energy. All these constraints are essentially independent of scales k > 0.1h/Mpc and associated nonlinear complications, yet agree well with more aggressive published analyses where nonlinear modeling is crucial. k [h/Mpc] Power Pg 0.012 +0.005 −0.004 124884 ± 18775 0.015 +0.003 −0.002 118814 ± 29400 0.018 +0.004 −0.002 134291 ± 21638 0.021 +0.004 −0.003 58644 ± 16647 0.024 +0.004 −0.003 105253 ± 12736 0.028 +0.005 −0.003 77699 ± 9666 0.032 +0.005 −0.003 57870 ± 7264 0.037 +0.006 −0.004 56516 ± 5466 0.043 +0.008 −0.006 50125 ± 3991 0.049 +0.008 −0.007 45076 ± 2956 0.057 +0.009 −0.007 39339 ± 2214 0.065 +0.010 −0.008 39609 ± 1679 0.075 +0.011 −0.009 31566 ± 1284 0.087 +0.

Perturbations of ultralight vector field dark matter

“…As shown above, scalar perturbations given by the C a, (1,2) components generate a gravity wave background with h + polarization in the k ∼ (Hma) 1/2 regime. If all the cosmological DM is generated by the vector field, it is possible to estimate the spectrum of gravity waves associated to such components and compare with the sensitivity of present and future detectors.…”

“…Despite the success of the collisionless cold dark matter (CDM) scenario in the description of the process of structure formation [1], still important difficulties are present regarding the predictions of simulations on sub-galactic scales. Indeed, dark matter (DM) only Nbody simulations predict cuspy profiles for the DM halo densities whereas observations of DM dominated objects, such as dwarf spheroidal galaxies, suggest more cored distributions (cusp-core problem) [2][3][4].…”

Observational probes of cosmic acceleration

“…To reach high precision on cosmological scales, the most promising route is to test for consistency between growth measurements from redshift-space distortions, which respond to the non-relativistic potential Ψ, and growth measurements from weak lensing. Implementing an approach suggested by Zhang et al (2007), Reyes et al (2010) present a form of this test that draws on redshift-space distortion measurements of SDSS luminous red galaxies by Tegmark et al (2006) and galaxy-galaxy lensing measurements of the same population. The precision of the test in Reyes et al (2010) is only ∼ 30%, limited mainly by the redshift-space distortion measurement, but this is already enough to rule out some otherwise viable models.…”

“…Since these first detections, the clustering of successively larger SDSS spectroscopic samples has been analyzed by several groups using different methods. Tegmark et al (2006) analyzed the DR4 LRG and main galaxy samples with a quadratic estimator for the power spectrum and redshiftspace distortion. Hütsi (2006) analyzed the monopole of the power spectrum of the LRG data set with the Feldman et al (1994) (FKP) method.…”

SUSY SU(5)×S 4 GUT flavor model for fermion masses and mixings with adjoint, large θ 13 PMNS

“…The plot of the ratio |m 3 /m 2 | and sum of light neutrino mass k m k as function of the lightest neutrino mass m lightest , which is m 1 (m 3 ) for NH (IH) mass spectrum, are shown in figure 3(a) and figure 3(b), respectively. Note that the horizontal lines in figure 3(b) represents the cosmological bound at 0.19 eV (black), corresponding to the combined observational data from [113][114][115][116][117][118][119][120][121][122], and the upper bounds 0.23 eV from Planck [123]. The ratio tends to a degenerate mass spectrum in both cases as the value of m lightest → 0.1eV which is disfavoured in the model.…”