Small scale structure predictions from discrete symmetry breaking - early quasar formation

Abstract

We discuss the local density fluctuations which arise due to the topological defects that appear after the phase transition of light pseudo-Goldstone bosons. It has been found that in a post-inflationary universe the fluctuations of these defects at large scales may have led to galaxy formation, while being consistent with the measurements of the cosmic microwave background radiation. Here we show that, at the local level, the fluctuations may be sufficiently large to lead to the production of smaller structures (ie quasars) with the observed distribution, which peaks at $z=2$ and drops rapidly for higher redshifts. Moreover it may be possible that a limited number of quasars are produced at redshifts of order 10, much earlier than what hot and cold dark matter scenarios predict. Although in this letter we work in the parameter space which is optimal for the generation of large scale structure as well, these features are generic for a wide class of domain wall models.