Stochastic Gravitational Wave Background generated by Cosmic String
  Networks: Velocity-Dependent One-Scale model versus Scale-Invariant Evolution
  We compute the power spectrum of the stochastic gravitational wave background
generated by cosmic string networks described by the Velocity-Dependent
One-Scale (VOS) model, for a wide range of macroscopic and microscopic
parameters. The VOS model --- which has been shown to provide an accurate
macroscopic description of the evolution of cosmic string networks --- is used
to demonstrate that cosmic string networks are unable to rapidly attain
scale-invariant evolution after the transition between the radiation and matter
eras. However, in computations of the stochastic gravitational wave background,
it is often assumed that the networks experience scale-invariant evolution
throughout cosmological history. We demonstrate that this assumption leads to
an underestimation of the amplitude and broadness of the peak of the spectrum,
that may consequently lead to inaccurate observational constraints on the
cosmic string tension.
