Testing gravity with galaxy-galaxy lensing and redshift-space distortions using CFHT-Stripe 82, CFHTLenS, and BOSS CMASS datasets

The combination of galaxy-galaxy lensing (GGL) and redshift space distortion of galaxy clustering (RSD) is a privileged technique to test general relativity predictions and break degeneracies between the growth rate of structure parameter f and the amplitude of the linear power spectrum sigma(8). We performed a joint GGL and RSD analysis on 250 sq. deg using shape catalogues from CFHTLenS and CFHT-Stripe 82 and spectroscopic redshifts from the BOSS CMASS sample. We adjusted a model that includes non-linear biasing, RSD, and Alcock-Paczynski effects. We used an N-body simulation supplemented by an abundance matching prescription for CMASS galaxies to build a set of overlapping lensing and clustering mocks. Together with additional spectroscopic data, this helps us to quantify and correct several systematic errors, such as photometric redshifts. We find f (z = 0.57) = 0.95 +/- 0.23, sigma(8)(z = 0.57) = 0.55 +/- 0.07 and Omega(m) = 0.31 +/- 0.08, in agreement with Planck cosmological results 2018. We also estimate the probe of gravity E-G = 0.43 +/- 0.10, in agreement with Lambda CDM-GR predictions of E-G = 0.40. This analysis reveals that RSD efficiently decreases the GGL uncertainty on Omega(m) by a factor of 4 and by 30% on sigma(8). We make our mock catalogues available on the Skies and Universe database.