LINEAR PERTURBATION-THEORY AND SPHERICAL OVERDENSITIES IN LAMBDA-NOT-EQUAL-0 FRIEDMANN MODELS

This paper presents various analytical results concerning the properties of large-scale structures in Friedmann models with a positive cosmological constant-LAMBDA. It shows, using linear perturbation theory, that for given density contrast delta and density parameter-OMEGA the effect of LAMBDA on the peculiar velocity field is at the most of order a few percent. It also shows that the number counts of galaxies inside the zero-velocity surface of spherical perturbations are nearly independent of LAMBDA. These results support the conclusion of two previous papers, that the cosmological constant-LAMBDA leaves little observable signature in the current dynamical state of the large-scale structure of the universe.