Multimessenger Constraints on Intergalactic Magnetic Fields from Flaring Objects

TL;DR

This paper uses observations of a blazar flare to constrain the strength and coherence length of intergalactic magnetic fields by analyzing their impact on the gamma-ray spectrum.

Contribution

It introduces a novel method to constrain intergalactic magnetic fields using multimessenger observations of blazar flares.

Findings

Strong IGMFs can significantly increase the reconstructed maximum gamma-ray energy.

Constraints on IGMF strength and coherence length are derived from the spectral analysis.

The approach links astrophysical observations to fundamental cosmological magnetic field properties.

Abstract

The origin of magnetic fields in the Universe is an open problem. Seed magnetic fields possibly produced in early times may have survived up to the present day close to their original form, providing an untapped window to the primeval Universe. The recent observations of high-energy neutrinos from the blazar TXS 0506+056 in association with an electromagnetic counterpart in a broad range of wavelengths can be used to probe intrinsic properties of this object and the traversed medium. Here we show that intergalactic magnetic fields (IGMFs) can affect the intrinsic spectral properties of this object reconstructed from observations. In particular, we point out that the reconstructed maximum gamma-ray energy of TXS 0506+056 can be significantly higher if IGMFs are strong. Finally, we use this flare to constrain both the magnetic-field strength and the coherence length of IGMFs.