Date Presented:

2022/07/1

Abstract:

A correlation between high-energy cosmic neutrinos and active galaxies with relativistic jets, known as blazars, has been remarked by several authors in the past few years. It has also been suggested that blazar flares (i.e. significant changes in flux) are ideal candidates for enhanced neutrino emission. So far, several works have discussed the connection between the X-ray and γ-ray flares with the neutrino signal, while many blazars that are positionally associated with high energy neutrinos detected by IceCube exhibit strong parsec-scale radio emission. In this work, we discuss the connection between the X-ray and radio frequencies during periods of enhanced neutrino emission. In our model, injection of relativistic hadrons into a compact region of the jet produces an X-ray and high-energy neutrino flare. At the same time, relativistic electron and positrons are produced through photo-hadronic interactions and photon-photon pair production (secondary pairs). We investigate the evolution of the electromagnetic cascade by following the secondary pairs upon their injection into an expanding spherical blob. Initially, the radio part of the cascade spectrum is self-absorbed, but the source becomes transparent to GHz frequencies as the blob expands, producing a delayed "radio flare". We investigate how the time lags between the X-ray and the radio flares are formed and what is the effect of physical parameters, such as the expansion velocity V$ _{exp}$ and the magnetic field strength B.

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