COSMOLOGICAL PERTURBATIONS AND THE RUNNING COSMOLOGICAL CONSTANT MODEL

Abstract

We study the matter density fluctuations in the running cosmological constant (RCC) model using linear perturbations in the longitudinal gauge. Using this observable, we calculate the growth rate of structures and the matter power spectrum, and compare these results to SDSS data and the available data for linear growth rate. The distribution of collapsed structures may also constrain models of dark energy. It is shown that the RCC model enhances departures from the ΛCDM model for both cluster number and cumulative cluster number predicted. In general, increasing the characteristic parameter ν leads to significant growth of the cluster number. We found that the theory of perturbations provides a useful tool to distinguish between the new model RCC and the standard cosmological model ΛCDM.