Electromagnetic Cascade Emission from Neutrino-Coincident Tidal Disruption Events

TL;DR

This paper models electromagnetic cascades and neutrino emissions from Tidal Disruption Events to understand their potential as sources of high-energy astrophysical neutrinos, providing constraints on emission zones and particle energies.

Contribution

It introduces a numerical model of EM cascades and neutrino emissions from TDEs, linking multi-wavelength observations with neutrino production constraints.

Findings

Gamma-ray observations limit the size of the emission region.

Expected neutrino event numbers are less than 0.1 for current searches.

X-ray and gamma-ray signals depend on the efficiency of pγ interactions.

Abstract

The potential association between Tidal Disruption Events (TDEs) and high-energy astrophysical neutrinos implies the acceleration of cosmic rays. These accelerated particles will initiate electromagnetic (EM) cascades spanning from keV to GeV energies by the processes related to neutrino production. We model the EM cascade and neutrino emissions by numerically solving the time-dependent transport equations and discuss the implications for AT2019dsg and AT2019fdr in the X-ray and $\gamma$-ray bands. We show that the $\gamma$-ray constraints from \emph{Fermi} can constrain the size of the radiation zone and the maximum energy of injected protons, and that the corresponding expected neutrino event numbers in follow-up searches are limited to be less than about 0.1. Depending on the efficiency of $p\gamma$ interactions, the X-ray and $\gamma$-ray signals can be expected closer to the peak of the optical-ultraviolet (OUV) luminosity, or to the time of the neutrino production.