Gravitational radiation from a bulk flow model

TL;DR

This paper simulates gravitational wave production during cosmological phase transitions using a simplified fluid model, providing parameterized spectra and improvements over previous approximations.

Contribution

It introduces a new simulation approach for gravitational radiation from fluid collisions during phase transitions, with enhanced accuracy and parameterized results.

Findings

Derived gravitational wave spectra as functions of key parameters

Improved on the envelope approximation with hydrodynamic simulations

Provided simple parameterizations for observational predictions

Abstract

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.