The power spectrum and bispectrum of SDSS DR11 BOSS galaxies I: bias and gravity

الأصل · EN

We analyse the anisotropic clustering of the Baryon Oscillation Spectroscopic Survey (BOSS) CMASS Data Release 11 sample, which consists of 690 827 galaxies in the redshift range 0.43 < z < 0.70 and has a sky coverage of 8 498 deg² corresponding to an effective volume of 6Gpc³. We fit the Fourier space statistics, the power spectrum and bispectrum monopoles to measure the linear and quadratic bias parameters, b₁ and b₂, for a non-linear non-local bias model, the growth of structure parameter f and the amplitude of dark matter density fluctuations parametrised by σ₈. We obtain b₁(z eff)¹.⁴⁰σ₈(z eff)=1.672± 0.060 and b₂⁰.³⁰(z eff)σ₈(z eff)=0.579±0.082 at the effective redshift of the survey, z eff=0.57. The main cosmological result is the constraint on the combination f⁰.⁴³(z eff)σ₈(z eff)=0.582±0.084, which is complementary to fσ₈ constraints obtained from 2-point redshift space distortion analyses. A less conservative analysis yields f⁰.⁴³(z eff)σ₈(z eff)=0.584±0.051. We ensure that our result is robust by performing detailed systematic tests using a large suite of survey galaxy mock catalogs and N-body simulations. The constraints on f⁰.⁴³σ₈ are useful for setting additional constrains on neutrino mass, gravity, curvature as well as the number of neutrino species from galaxy surveys analyses (as presented in a companion paper).