Identifying Episodic Gravitational Wave and High-Energy Neutrino Sources in Starburst Galaxies

Supermassive black hole mergers involving spin flips can accelerate high-energy particles via their relativistic precessing jets, leading to the production of high-energy neutrinos and gravitational waves (GWs). In star-forming regions, massive stars often form in groups, facilitating second-generation mergers of their remnants with varying spin orientations. Supporting evidence from GW data bolsters this scenario. Previously, we had proposed that stellar mass BH mergers, particularly in M82, with associated spin-flip dynamics, similarly enable the acceleration of energetic particles, resulting in high-energy neutrinos and photons, and ultimately GWs. At cosmic scales, only GWs and neutrinos are detectable. This study extends our previous argument to encompass starburst and normal galaxies across cosmic time, suggesting that these galaxies may surpass active galactic nuclei (AGN) in contributing to the flux of ultra-high-energy particles observed on Earth. Both types of sources contribute to the cosmic neutrino and GW backgrounds, particularly at lower frequencies. We propose a two-step search strategy to identify these episodic sources, emphasizing the importance of incorporating both luminosity and flux density. At higher star formation rates and thus higher absolute FIR luminosities, the likelihood of capturing an ongoing active event significantly increases. Therefore, we must prioritize sources with peak luminosities at the detection threshold for a given flux density, optimizing for real-time event observation.