High-energy neutrino emission from tidal disruption event outflow-cloud interactions

TL;DR

This paper investigates how tidal disruption events (TDEs) with outflow-cloud interactions could significantly contribute to high-energy neutrinos detected by IceCube, especially below 0.3 PeV, and constrains their physical parameters.

Contribution

It introduces a detailed outflow-cloud model for TDEs and quantifies their potential contribution to the diffuse high-energy neutrino flux, providing new constraints on physical parameters.

Findings

TDEs can account for about 80% of neutrinos at 0.3 PeV.

TDEs contribute around 18% below 0.1 PeV.

Total TDE contribution is approximately 24%.

Abstract

Tidal disruption events (TDEs), characterized by their luminous transients and high-velocity outflows, have emerged as plausible sources of high-energy neutrinos contributing to the diffuse neutrino. In this study, we calculate the contribution of TDEs to the diffuse neutrino by employing the outflow-cloud model within the TDE framework. Our analysis indicates that the contribution of TDEs becomes negligible when the redshift $Z$ exceeds 2. Employing a set of fiducial values, which includes outflow energy $E_{\rm kin}=10^{51}$ erg, a proton spectrum cutoff energy $E_{\rm p,max}=100$ PeV, a volume TDE rate $\dot{N}=8 \times 10^{-7}\ \rm Mpc^{-3}\ year^{-1}$, covering fraction of clouds $C_V=0.1$, energy conversion efficiency in the shock $\eta =0.1$, and a proton spectrum index $\Gamma=-1.7$, we find that TDEs can account for approximately 80\% of the contribution at energies around 0.3 PeV. Additionally, TDEs still contribute around 18\% to the IceCube data below 0.1 PeV and the total contribution is $\sim 24^{+2}_{-15}\%$. In addition, we also discuss the potential influence of various parameter values on the results in detail. With the IceCube data, we impose constraints on the combination of the physical parameters, i.e., $C_{f}=\dot{N}E_{\rm kin}C_{\rm v}\eta$. Future observations or theoretical considerations would fix some physical parameters, which will help to constrain some individual parameters of TDEs.