Formation of large-scale structure from cosmic-string loops and cold dark matter

Abstract

Cosmic strings are one-dimensional concentrations of energy which can form as the result of a phase transition in the early Universe. Recent interest has been generated by the possibility that strings could lead to the formation of galaxies and large-scale structure^1–9. Here we present some results from a numerical simulation of the formation of large-scale structure from cosmic-string loops. We find that even though we require Gµ< 2 × 10⁶ (where µ is the mass per unit length of the string) to give a low enough autocorrelation amplitude, there is excessive power on smaller scales, so that galaxies would be more dense than observed. The large-scale structure does not include a filamentary or connected appearance and shares with more conventional models based on gaussian perturbations the lack of cluster–cluster correlation at the mean cluster separation scale as well as excessively small bulk velocities on these scales.