Prompt And Delayed Radio Bangs At Kilohertz By SN 1987A: A Test For Graviton-Photon Conversion

TL;DR

This work addresses testing graviton–photon conversion (the Gertsenshtein effect) as a probe of enormous gravitational bursts from supernovae by predicting low-frequency radio signatures. It develops exact solutions for GW↔EW oscillations in stationary magnetic fields, introduces a generalized Zel'dovich dispersion law for refractive media, and analyzes both single-coherence and multi-coherence conversion regimes, including cosmic-background implications. Applying the framework to SN1987A, it estimates Earth- and Jove-based fluxes and highlights the crucial role of coherence length and delays in determining detectability, with the most favorable signals arising for distant, incoherent interstellar fields that produce long-delayed radio tails. The results provide a concrete theoretical basis for seeking gravitational-wave–induced radio signals in the tens-of-kilohertz band, linking GW physics with low-frequency radio astronomy and SN explosion dynamics.

Abstract

A sequence of prompt and delayed radio signals at tens of kilohertz should reach the Earth (or Jupiter) due to graviton--photon conversion in interstellar as well as local planetary magnetic fields. These radio fluxes may be a detectable probe of a huge gravitational burst expected from Supernovae explosions. The earliest prompt radio signal, coinciding with the neutrino burst, is due to conversion in the terrestrial (or Jovian) magnetic field and is below the micro-Jansky (or milli-Jansky) level for a galactic Supernova like SN1987A. A later radio signal, a ``tail'', due to the same graviton - radio wave conversion in random interstellar fields will maintain a relic radio ``noise'' for hundreds or thousands of years and might even be still detectable by a very sensitive network of satellite antennas at the kilohertz band. Exact solutions are presented here for the graviton-photon conversion in a refractive medium, as well as their consequences for high energy supernovae and the 2.726 K background radiation.