Gravitational Wave Background from Population III Stars

TL;DR

This paper estimates the gravitational wave background from Population III stars, showing it could be detectable by future interferometers and provide insights into early universe star formation history.

Contribution

The study combines hydrodynamic simulations with GW waveform calculations to predict a potentially detectable GW background from Pop III stars.

Findings

GW background peaks at Ω_GW ~ 10^{-10} in 1-10 Hz range

Neutrino emissions dominate GW signals at frequencies below 10 Hz

Detection prospects depend on Pop III star formation rates

Abstract

We estimate the gravitational wave (GW) background from Population III (Pop III) stars using the results from our hydrodynamic simulations (Suwa et al. 2007). We calculate gravitational waveforms from matter motions and anisotropic neutrino emissions for single Pop III stars. We find that the GW amplitudes from matter motions are dominant until just after bounce, but those from neutrinos dominate later on at frequencies below $\sim 10$ Hz in the GW spectrum. Computing the overall signal produced by the ensemble of such Pop III stars, we find that the resultant density parameter of the GW background peaks at the amplitude of $\Omega_\mathrm{GW}\sim 10^{-10}$ in the frequency interval $\sim 1-10$ Hz. We show that such signals, depending on the formation rate of Pop III stars, can be within the detection limits of future planned interferometers such as DECIGO and BBO in the frequency interval of $\sim 0.1-1$ Hz. Our results suggest that the detection of the GW background from Pop III stars can be an important tool to supply the information about the star formation history in the early universe.