We use measurements from the Planck satellite mission and galaxy redshift surveys over the last decade to test three of the basic assumptions of the standard model of cosmology , \Lambda CDM : the spatial curvature of the universe , the nature of dark energy and the laws of gravity on large scales .
We obtain improved constraints on several scenarios that violate one or more of these assumptions .
We measure w _ { 0 } = -0.94 \pm 0.17 ( 18 % measurement ) and 1 + w _ { a } = 1.16 \pm 0.36 ( 31 % measurement ) for models with a time-dependent equation of state , which is an improvement over current best constraints ( ) .
In the context of modified gravity , we consider popular scalar tensor models as well as a parametrization of the growth factor .
In the case of one-parameter f ( R ) gravity models with a \Lambda CDM background , we constrain B _ { 0 } < 1.36 \times 10 ^ { -5 } ( 1 \sigma C.L .
) , which is an improvement by a factor of 4 on the current best ( ) .
We provide the very first constraint on the coupling parameters of general scalar-tensor theory and stringent constraint on the only free coupling parameter of Chameleon models .
We also derive constraints on extended Chameleon models , improving the constraint on the coupling by a factor of 6 on the current best ( ) .
We also measure \gamma = 0.612 \pm 0.072 ( 11.7 % measurement ) for growth index parametrization .
We improve all the current constraints by combining results from various galaxy redshift surveys in a coherent way , which includes a careful treatment of scale-dependence introduced by modified gravity .