Impact of Galactic magnetic field modelling on searches of point sources via UHECR-Neutrino correlations

TL;DR

This study investigates how different models of the Galactic magnetic field affect the sensitivity and limits of ultra-high energy cosmic ray and neutrino point source correlation searches, revealing a significant impact of magnetic field assumptions.

Contribution

The paper compares various magnetic field models, including the JF12 configuration and turbulence, on neutrino source detection sensitivity, introducing a new parameterization of the JF12 random component.

Findings

Magnetic field assumptions influence detection sensitivity by 15-26%.

No correlations found between UHECRs and neutrinos under current models.

Different magnetic field models alter the minimum neutrino flux required for discovery.

Abstract

We use the Jansson-Farrar JF12 magnetic field configuration in the context of point source searches by correlating the Telescope Array ultra-high energy cosmic ray data and the IceCube-40 neutrino candidates. As expected, we have found no correlations, thus, we devote this paper to the study of the effect of different magnetic field hypotheses on the minimum neutrino source flux strength required for a $5\sigma$ discovery and the derived $90\%$ CL upper limits. In this study we present a comparison between the JF12 field, that includes a combination of regular and random field components, and the standard turbulent magnetic field used in previous correlation analyses. For a wider perspective, we also incorporate in our comparison the cases of no magnetic field and the JF12 regular component alone and consider different power law indices $\alpha=2,\alpha=2.3$ for the neutrino point source flux. Collaterally, a novel parameterisation of the JF12 random component is introduced. We have observed that the discovery potential for a point source search is sensitive to changes in the magnetic field assumptions, being the difference between the models mentioned before between 15% and 26%.