Abstract
We show how it is possible to test general relativity and di erent models of gravity via Redshift-Space Distortions using forthcoming cosmological galaxy surveys. However, the theoretical models currently used to interpret the data often rely on simpli- fications that make them not accurate enough for precise measurements. We will discuss improvements to the theoretical modeling at very large scales, including wide-angle and general relativistic corrections; we then show that for wide and deep surveys those cor- rections need to be taken into account if we want to measure the growth of structures at a few percent level, and so perform tests on gravity, without introducing systematic errors. Finally, we report the results of some recent cosmological model tests carried out using those precise models.
Highlights
The ΛCDM+GR paradigm is at the moment our best explanation for current observations; its explanation for the accelerated expansion of the universe is based on a phenomenological model with no strong theoretical foundation
Observations of Redshift Space Distortions (RSD) in spectroscopic galaxy surveys are a promising way to study the pattern and the evolution of the Large Scale Structure of the Universe [13, 14], as they provide constraints on the amplitude of peculiar velocities induced by structure growth, thereby allowing tests of the theory of gravity governing the growth of those perturbations
We refer to a class of Unified Dark Matter (UDM) scalar field models in which a single scalar field is responsible for both the late time accelerated expansion of the Universe and the growth of structures; for details about this models see [9, 10, 40]
Summary
The ΛCDM+GR paradigm is at the moment our best explanation for current observations; its explanation for the accelerated expansion of the universe is based on a phenomenological model with no strong theoretical foundation This acceleration can be explained introducing a dark energy component, or with modifications of Einstein’s General Relativity theory of gravitation on cosmological scales (see [1] for a review on different dark energy and modified gravity models). EPJ Web of Conferences played an important role in developing our standard cosmological model and will play an essential role in our investigations on the origin of cosmic acceleration In this proceeding we show how we can use measurements of the clustering of galaxies to test cosmological models and we present corrections to the standard analysis that will need to be introduced when considering galaxies with very large separations. Clustering analyses are complementary to other probes, since they depend on temporal metric perturbations, while e.g. weak lensing depends on the sum of the temporal and spatial metric perturbations and the Integrated Sachs-Wolfe effect depends on the sum of their derivatives [12]
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