Neutrino detection rates from lepto-hadronic model simulations of bright blazar flares

TL;DR

This study models neutrino production in blazar flares using lepto-hadronic simulations, revealing that calorimetric estimates often overpredict neutrino rates by about ten times when gamma-ray emission is proton-synchrotron dominated.

Contribution

It introduces a time-dependent lepto-hadronic modeling approach to accurately estimate neutrino production in blazar flares, challenging previous calorimetric estimates.

Findings

Calorimetric estimates overpredict neutrino rates by a factor of ~10.

Proton-synchrotron dominated gamma-ray emission leads to overestimation.

Time-dependent modeling provides more accurate neutrino flux predictions.

Abstract

There is mounting evidence that blazars are the sources of part of the very-high-energy astrophysical neutrino flux detected by IceCube. In particular, there have been several spatial and temporal coincidences of individual IceCube neutrino events with flaring blazars, the most prominent of them being IceCube-170922A, coincident with a multi-wavelength flare of TXS~0506+056. Motivated by this, we used the time-dependent lepto-hadronic code OneHaLe to model the spectral energy distributions and light curves of a sample of bright $\gamma$-ray flares of blazars detected by Fermi-LAT, for which Kreter et al. (2020) provided calorimetric estimates of the expected neutrino detection rates. Flares were modelled with temporal changes of the proton injection spectra. Our analysis shows that the calorimetric approach overestimates the increase in neutrino production by a factor of typically $\sim 10$ if the $\gamma$-ray emission is dominated by proton-synchrotron radiation.