Odessa I.I. Mechnikov National University and Istanbul Technical University
Abstract: Cosmic structures (e.g. galaxies, group and clusters of galaxies) are formed due to gravitational interaction. In the weak field approximation this interaction is defined by the gravitational potential. In General Relativity, the equation for the gravitational potential is determined by the theory of perturbations. For cosmological models it is necessary to take into account the dynamical nature of the background geometry (which is usually taken in the form of the Friedmann metric). Since the energy density of the matter depends on metric, we show that the gravitational potential at cosmological scales satisfies the Helmholtz type equation, rather than the Poisson equation. Therefore, it has the Yukawa potential form. The Yukawa interaction range is time dependent and is of the order of 3700 Mpc at the present time. At small distances from an inhomogeneity (e.g. a galaxy), it has the Newtonian limit. Our approach works at all cosmological scales and incorporates linear and nonlinear effects with respect to energy density fluctuations.
Yer: MSGSÜ Bomonti Binası, Fizik Bölümü
Tarih: 14 Aralık 2017 Perşembe, 15:00