SCREENING OF GRAVITATIONAL INTERACTIONS AND ITS ASTROPHYSICAL MANIFESTATIONS

Screening of the Newtonian potential of a moving test body in a homoge neous Maxwellian gas of gravitating bodies is investigated on the basi s of the collisionless kinetic equation and the Poisson equation. The modified potential is expressed in terms of the test particle velocity and the gravitational susceptibility of the system. Since all bodies in such a system execute a thermal motion, a renormalized gravitationa l potential in the system can be determined by way of averaging the te st-body potential over the body velocities with the Maxwellian distrib ution function. It is found that the resultant renormalized potential not only decays faster than the Newtonian potential but also oscillate s with the period on order of the Jeans length. A dark matter allowanc e in the system gives rise to a significant decrease in the oscillatio n period. The observable oscillations of the tail ends of the correlat ion functions of galaxies and Abell clusters testify to the oscillatin g character of the screened potential, and the observable period of th ese oscillations enables us to estimate the Jeans wavenumber for the d ark matter.