Probing stochastic inter-galactic magnetic fields using blazar-induced gamma ray halo morphology

TL;DR

This paper investigates how inter-galactic magnetic fields influence the shape of gamma ray halos around blazars, using simulations and a new statistical method to infer magnetic field properties.

Contribution

It introduces an improved Q-statistics method for analyzing halo morphology, sensitive to magnetic field strength, coherence scale, and helicity, based on extensive numerical simulations.

Findings

Q-statistics sensitivity to magnetic field properties

Identification of a new feature enhancing analysis power

Validation through simulated halo data

Abstract

Inter-galactic magnetic fields can imprint their structure on the morphology of blazar-induced gamma ray halos. We show that the halo morphology arises through the interplay of the source's jet and a two-dimensional surface dictated by the magnetic field. Through extensive numerical simulations, we generate mock halos created by stochastic magnetic fields with and without helicity, and study the dependence of the halo features on the properties of the magnetic field. We propose a sharper version of the Q-statistics and demonstrate its sensitivity to the magnetic field strength, the coherence scale, and the handedness of the helicity. We also identify and explain a new feature of the Q-statistics that can further enhance its power.