Dissipationless clustering of neutrinos in cosmic-string-induced wakes.

Abstract

Velocity perturbations which form in the wake of long straight strings moving at a relativistic speed can generate significant large-scale structure in the Universe. With neutrinos as dark matter, a considerable fraction of all galaxies forms in large-scale sheets. Here we study the dissipationless clustering of neutrinos in cosmic-string-induced wakes using an analysis based on the Gilbert equation, i.e., taking into account the velocity dispersion of neutrinos. We compare the results with simple heuristic analyses.