Particle Physics Seminar

The nature of dark energy is one of the deepest mysteries of modern cosmology and greatest challenges of contemporary particle physics.
Little is known about dark energy directly, but we can observe its effects on the expansion history of the universe and evolution of large-scale structure. So far, the influence of dark energy on nonlinear aspects of structure formation has remained relatively unexplored. We perform peak counts in weak lensing maps, as a first step in a more comprehensive exploration of the dependence of nonlinear structure formation on dark energy in general, which we will outline.

Unlike the common method of counting clusters and determining their masses, weak lensing peak counts depend neither on cluster mass estimates, completeness of survey, nor projections effects, which all pose potential observational challenges. Peak counts thus present a very direct way of measuring the influence of dark energy on nonlinear structure formation. The price is that they are harder to predict theoretically, and simulations are required for comparison to observations. We demonstrate the whole pipeline of our work, from setting up the simulations to obtaining projected constraints on dark energy for upcoming surveys.