Non-linear effects on the BAO and higher-order statistics in alternative theories of gravity

by Miguel Zumalacarregui

Wednesday 20 Apr 2016, 11:30 → 12:30 Europe/Zurich

4/2-011 - TH common room (CERN)

The scale of Baryon Acoustic Oscillations (BAO) imprinted in the matter distribution is known to suffer sub-percent deviations from being a perfect standard ruler due to non-linear corrections. I will give an overview of historical and recent developments in alternative theories of gravity and the hi_class code, a new tool to study their cosmological implications (www.hiclass-code.net). Then I will present the first computation of the BAO shift based on perturbation theory and a peak-background split, valid for a large class of models. The BAO shift is modified by the enhanced growth of linear perturbations, as well as by novel, non-linear gravitational effects. The prediction can be larger than the standard value by 45-82% at z=0 for simple alternatives to a cosmological constant, and in some cases presents a characteristic time evolution. Although too small to affect conventional BAO analyses, these effects leave an imprint in the matter bispectrum and might have implications for BAO reconstruction in theories other than Einstein's.