Exploring the posterior surface of the large scale structure reconstruction

Understand

The large scale structure (LSS) of the universe is generated by the linear density gaussian modes, which are evolved into the observed nonlinear LSS.

• The posterior surface of the modes is convex in the linear regime, leading to a unique global maximum (MAP), but this is no longer guaranteed in the nonlinear regime.
• In this paper we investigate the nature of posterior surface using the recently developed MAP reconstruction method, with a simplified but realistic N-body simulation as the forward model.
• The reconstruction method uses optimization with analytic gradients from back-propagation through the simulation.