Gravitational radiation from a bulk flow model

Understand

We perform simulations in a simple model that aims to mimic the hydrodynamic evolution of a relativistic fluid during a cosmological first-order phase transitions.

• The observable we are concerned with is hereby the spectrum of gravitational radiation produced by colliding fluid shells.
• We present simple parameterizations of our results as functions of the wall velocity, the duration of the phase transition and the latent heat.
• We also improve on previous results in the envelope approximation and compare with hydrodynamic simulations.