Unveiling the cosmological information beyond linear scales: Forecasts for sufficient statistics

Abstract

Beyond the linear regime, Fourier modes of cosmological random fields become correlated, and the power spectrum of density fluctuations contains only a fraction of the available cosmological information. To unveil this formerly hidden information, the A* non-linear transform was introduced; it is optimized both for the non-linearities induced by gravity and observational noise. Quantifying the resulting increase of our knowledge of cosmological parameters, we forecast the constraints from the angular power spectrum and that of A* from l ~ 200 to 3000 for upcoming galaxy surveys such as: the Wide-Field Infrared Survey Telescope, the Large Synoptic Survey Telescope, Euclid, the Hyper Suprime-Cam and the Dark Energy Survey. We find that at low redshifts this new data analysis strategy can double the extracted information, effectively doubling the survey area. To test the accuracy of our forecasting and the power of our data analysis methods, we apply the A* transformation to the latest release of the Canada-France-Hawaii Telescope Legacy Survey Wide. While this data set is too sparse to allow for more than modest gains (~1.1-1.2), the realized gain from our method is in excellent agreement with our forecast, thus verifying the robustness of our analysis and prediction pipelines.