COSMIC STRINGS, LOOPS, AND LINEAR GROWTH OF MATTER PERTURBATIONS

Abstract

We describe a detailed study of string-seeded structure formation using high resolution numerical simulations in open universes and those with a non-zero cosmological constant. We provide a semi-analytical model which can reproduce these simulation results including the effect from small loops chopped of by the string network. A detailed study of cosmic string network properties regarding structure formation is also given, including the correlation time, the topological analysis of the source spectrum, the correlation between long strings and loops, and the evolution of long-string and loop energy densities. For models with Γ=Ω h=0.1 -0.2 and a cold dark matter background, we show that the linear density fluctuation power spectrum induced by cosmic strings has both an amplitude at 8 h-1 Mpc, σ8, and an overall shape which are consistent within uncertainties with those currently inferred from galaxy surveys. The cosmic string scenario with hot dark matter requires a strongly scale-dependent bias in order to agree with observations.