Clustering of cosmic string loops

TL;DR

This paper re-examines the distribution of cosmic string loops within galaxies, showing that only larger loops are captured and challenging previous estimates of their abundance based on gravitational capture.

Contribution

It introduces a detailed spherical galaxy formation model including the gravitational rocket effect to refine predictions of loop capture.

Findings

Only loops above a certain size are captured by galaxies.

The number of captured loops is much smaller than previous estimates.

The gravitational rocket effect significantly impacts loop capture dynamics.

Abstract

Observational effects of cosmic string loops depend on how loops are distributed in space. Chernoff \cite{Chernoff} has argued that loops can be gravitationally captured in galaxies and that for sufficiently small values of $G\mu$ their distribution follows that of dark matter, independently of the loop's length. We re-analyze this issue using the spherical model of galaxy formation with full account taken of the gravitational rocket effect -- loop accelerated motion due to asymmetric emission of gravitational waves. We find that only loops greater than a certain size are captured and that the number of captured loops is orders of magnitude smaller than estimated by Chernoff.