Testing general relativity with the multipole spectra of the SDSS luminous red galaxies

Abstract

As a test of general relativity on cosmological scales, we measure the γparameter for the growth rate of density perturbations using the redshift-space distortion of the luminous red galaxies in the Sloan Digital Sky Survey (SDSS). Assuming the cosmological constant model, which matches the results of the WMAP experiment, we find γ=0.62+1.8(σ_8-0.8) \pm 0.11 at 1-sigma confidence level, which is consistent with the prediction of general relativity, γ\simeq0.55\sim0.56. Rather high value of σ_8(\geq0.87) is required to be consistent with the prediction of the cosmological DGP model, γ\simeq0.68.

Figures (3)

• Figure 1: (a, Left) Monopole power spectrum as a function of the wave number. The dark (black) points represent this work, the light (green) points the previous result HutsiAB. (b, Right) Quadrupole power spectrum divided by the monopole spectrum. The solid curve is the theoretical curve of the $\Lambda$CDM model.
• Figure 2: The bias $b(k_i)$ obtained from our numerical method. The three curves correspond to $\sigma_8=0.9,~0.8,~0.7$ and the other parameters are the same as those of Figure 1-b. For the case $\sigma_8=0.8$ the errors are estimated from those of $P(k_i)$. The dashed curve is $b(k)=1.2[1+0.2(k/0.1h{\rm Mpc}^{-1})^{1/2}]$.
• Figure 3: (a, Left) $\Delta\chi^2$ in the $\gamma$-$\sigma_v$ plane. We fixed the normalization of the mass power spectrum as $\sigma_8=0.7$ (dotted curves), $\sigma_8=0.8$ (solid curves), and $\sigma_8=0.9$ (dashed curves), respectively. The contour levels are $\Delta\chi^2=2.3$ (inner curves) and 6.2 (outer curves), which correspond to the 1-sigma and 2-sigma confidence levels of the $\chi^2$ distribution. The other parameters are fixed as $\Omega_m=0.28$, $n_s=0.96$, and $h=0.7$.Komatsu (b, Right) Same as the left (a), except here we used the expansion history of the DGP model.