Zeldovich approximation and the probability distribution for the smoothed density field in the nonlinear regime

Abstract

The study of large-scale structure in the Universe is often based on the observed density distribution of matter smoothed by a suitable filter function. The probability distribution for this smoothed density field in the nonlinear regime is studied using the Zel'dovich approximation. When the shear term of the velocity field is not too large, one can obtain a reasonably good analytic approximation tho this probability distribution. The properties of this distribution are discussed and compared with other attempts along similar lines.