Tomohiro Nakama (RESCEU) 14:00- Title: Setting up the initial condition for the formation of primordial black holes by asymptotic expansion Abstract: We constitute a solution of the Einstein equations for a spherically symmetric perturbed region in the radiation dominated Friedmann Universe in order to set up the initial condition for the formation of primordial black holes. The analytic solution is obtained in terms of the asymptotic expansion with respect to the ratio of the size of the perturbed region to the Hubble radius, and it is fully determined by the initial profile of the superhorizon curvature perturbations. Solv- ing the recurrence formulae up to the eighth order in the expansion parameter, we show that the errors associated with truncation remain small enough for various initial curvature profiles to provide the ini- tial condition for the full numerical analysis of primordial black hole formation. |