Dynamical particles in spatially flat FLRW space-times

Abstract

Abstract Metrics of dynamical point particles embedded in spatially flat FLRW space-times are derived as isotropic solutions of the Einstein equations with the energy–momentum tensor of a perfect fluid. These particles are produced by central singularities of the fluid density but without changing the pressure of the asymptotic FLRW space-times. It is shown that each particle gets a dynamical photon sphere before a critical instant when two dynamical apparent horizons arise just on the photon sphere evolving then as C-curves. The angular radius of the shadow associated to the photon sphere is derived and compared with the known results.