Abstract
The late universe contains a wealth of information about fundamental physics and gravity, wrapped up in non-Gaussian fields. To make use of as much information as possible, it is necessary to go beyond two-point statistics. Rather than going to higher-order N-point correlation functions, we demonstrate that the probability distribution function (PDF) of spheres in the matter field (a one-point function) already contains a significant amount of this non-Gaussian information. The matter PDF dissects different density environments which are lumped together in two-point statistics, making it particularly useful for probing modifications of gravity or expansion history. Our approach in Cataneo et al. 2021 extends the success of Large Deviation Theory for predicting the matter PDF in ΛCDM in these “extended” cosmologies. A Fisher forecast demonstrates the information content in the matter PDF via constraints for a Euclid-like survey volume combining the 3D matter PDF with the 3D matter power spectrum. Adding the matter PDF halves the uncertainties on parameters in an evolving dark energy model, relative to the power spectrum alone. Additionally, the matter PDF contains enough non-linear information to substantially increase the detection significance of departures from General Relativity, with improvements up to six times the power spectrum alone. This analysis demonstrates that the matter PDF is a promising non-Gaussian statistic for extracting cosmological information, particularly for beyond ΛCDM models.
Highlights
Academic Editors: Mariusz P.In recent decades, cosmology has moved solidly into a data-driven science
These differences in shape and redshift dependence are what allows the probability distribution function (PDF) to break degeneracies between standard cosmological parameters and modified gravity
The analytic framework described here has been successfully applied to ΛCDM universes along with extensions including primordial non-Gaussianity [24] and massive neutrinos [22]
Summary
Academic Editors: Mariusz P.In recent decades, cosmology has moved solidly into a data-driven science. The current standard model of cosmology, called ΛCDM, consists of a cosmological constant as the dark energy component (Λ), and cold (non-relativistic) dark matter (CDM) as its principle components. While CMB data is very valuable in extracting cosmological information, in the push to sub-percent measurements of standard cosmological parameters, and in testing non-standard cosmologies, the large-scale structure (LSS) of the universe is the most promising complementary tool. The large-scale structure provides a window to the expansion history of the universe, which makes it an exciting probe of dynamical dark energy and modifications to gravity. These extensions to the standard cosmology are one of the principle science goals of current and upcoming missions like
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