We present the power spectrum of the reconstructed halo density field derived from a sample of Luminous Red Galaxies ( LRGs ) from the Sloan Digital Sky Survey Seventh Data Release ( DR7 ) .
The halo power spectrum has a direct connection to the underlying dark matter power for k \leq 0.2 h Mpc ^ { -1 } , well into the quasi-linear regime .
This enables us to use a factor of \sim 8 more modes in the cosmological analysis than an analysis with k _ { max } = 0.1 h Mpc ^ { -1 } , as was adopted in the SDSS team analysis of the DR4 LRG sample ( 90 ) .
The observed halo power spectrum for 0.02 < k < 0.2 h Mpc ^ { -1 } is well-fit by our model : \chi ^ { 2 } = 39.6 for 40 degrees of freedom for the best-fitting \Lambda CDM model .
We find \Omega _ { m } h ^ { 2 } ( n _ { s } / 0.96 ) ^ { 0.13 } = 0.141 ^ { +0.009 } _ { -0.012 } for a power law primordial power spectrum with spectral index n _ { s } and \Omega _ { b } h ^ { 2 } = 0.02265 fixed , consistent with CMB measurements .
The halo power spectrum also constrains the ratio of the comoving sound horizon at the baryon-drag epoch to an effective distance to z = 0.35 : r _ { s } / D _ { V } ( 0.35 ) = 0.1097 ^ { +0.0039 } _ { -0.0042 } .
Combining the halo power spectrum measurement with the WMAP 5 year results , for the flat \Lambda CDM model we find \Omega _ { m } = 0.289 \pm 0.019 and H _ { 0 } = 69.4 \pm 1.6 km s ^ { -1 } Mpc ^ { -1 } .
Allowing for massive neutrinos in \Lambda CDM , we find \sum m _ { \nu } < 0.62 eV at the 95 % confidence level .
If we instead consider the effective number of relativistic species N _ { eff } as a free parameter , we find N _ { eff } = 4.8 ^ { +1.8 } _ { -1.7 } .
Combining also with the Kowalski et al .
( 45 ) supernova sample , we find \Omega _ { tot } = 1.011 \pm 0.009 and w = -0.99 \pm 0.11 for an open cosmology with constant dark energy equation of state w .
The power spectrum and a module to calculate the likelihoods is publicly available at http : //lambda.gsfc.nasa.gov/toolbox/lrgdr/ .