At the Highest-Frequency Frontier: Thermal Gravitational Waves from Supernovae

Abstract

Core-collapse supernovae can be powerful sources of high-frequency gravitational waves (GWs) as the extreme temperatures and densities in the core allow a considerable number of gravitons to be produced thermally. We present the first systematic calculation of the thermal GW spectrum of a core-collapse supernova. By evaluating the dominant emission channels---including electron and proton photoproduction ($\gamma e^{-}\to h{e}^{-}$, $\gamma p\to hp$) and gravitational bremsstrahlung ($e^{-}p\to e^{-}ph$, $e^{-}{e}^{-}\to e^{-}{e}^{-}h$)---we find that a core-collapse supernova generates a total thermal GW luminosity of $1.27\times 10^{26}$ W, approximately 18 orders of magnitude larger than that of the Sun. The thermal GW spectrum peaks at energies of $\mathcal{O}(0.1\mathrm{GeV})$, extending the predicted spectrum of known GW sources to an unprecedented high-frequency regime. Our results provide a benchmark thermal GW spectrum at the high-frequency frontier.

arXiv comment16 pages, 5 figures, 1 table. Code available at https://github.com/ChitsinYin/Supernova-Graviton-MC