Testing general relativity with growth rate measurement from Sloan Digital Sky Survey  III. Baryon Oscillations Spectroscopic Survey galaxies
Abstract
The measured redshift (z) of an astronomical object is a combination of Hubble recession, gravitational redshift and peculiar velocity. The lineofsight distance to a galaxy inferred from redshift is affected by the peculiar velocity component of galaxy redshift, which is observed as an anisotropy in the correlation function. This anisotropy allows us to measure the linear growth rate of matter (fσ_{8}). We measure the fσ_{8} at z = 0.57 using the CMASS sample from Data Release 11 of Sloan Digital Sky Survey III (SDSS III) Baryon Oscillations Spectroscopic Survey (BOSS). The galaxy sample consists of 690 826 massive galaxies in the redshift range 0.430.7 covering 8498 deg^{2}. Here, we report the first simultaneous measurement of fσ_{8} and background cosmological parameters using Convolution Lagrangian Perturbation Theory (CLPT) with Gaussian streaming model (Gaussian Streaming Redshift Space Distortions  GSRSD). We arrive at a constraint of fσ_{8} = 0.462 ± 0.041 (9 per cent accuracy) at effective redshift (bar{z}=0.57) when we include Planck cosmic microwave background likelihood while marginalizing over all other cosmological parameters. We also measure bσ_{8} = 1.19 ± 0.03, H(z = 0.57) = 89.2 ± 3.6 km s^{1} Mpc^{1} and D_{A}(z = 0.57) = 1401 ± 23 Mpc. Our analysis also improves the constraint on Ω_{c} h^{2} = 0.1196 ± 0.0009 by a factor of 3 when compared to the Planck only measurement(Ω_{c} h^{2} = 0.1196 ± 0.0031). Our results are consistent with Planck Λ cold dark matter (CDM)general relativity (GR) prediction and all other CMASS measurements, even though our theoretical models are fairly different. This consistency suggests that measurement of fσ_{8} from redshift space distortions at multiple redshifts will be a sensitive probe of the theory of gravity that is largely model independent, allowing us to place modelindependent constraints on alternative models of gravity.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 October 2015
 DOI:
 10.1093/mnras/stv1737
 arXiv:
 arXiv:1504.02100
 Bibcode:
 2015MNRAS.453.1754A
 Keywords:

 gravitation;
 galaxies: haloes;
 galaxies: statistics;
 cosmological parameters;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 10 pages, 7 figures, video summary on youtube: https://www.youtube.com/watch?v=L7lQspwpZA&