A roadmap for searching cosmic rays correlated with the extraterrestrial neutrinos seen at IceCube

TL;DR

This paper develops a sky map to identify regions where ultrahigh energy cosmic rays are likely correlated with astrophysical neutrinos observed by IceCube, considering magnetic deflections and composition models.

Contribution

It provides a detailed methodology for constructing correlation regions between UHECRs and neutrino sources, incorporating magnetic field models and cosmic ray composition.

Findings

Regions outside the Galactic plane show stronger correlation with neutrino tracks.

The angular size of correlated regions varies with energy, e.g., ~5° at 150 EeV.

The sky map serves as a guide for future UHECR excess searches.

Abstract

We have built regions in a Sky map where it should be expected the arrival of 120 EeV ultrahigh energy cosmic rays (UHECR) directionally correlated with the latest astrophysical neutrino tracks observed at IceCube, which are taken as point sources. In order to calculate these arrival directions we have considered contributions to the cosmic rays deflections originated by the galactic and the extragalactic magnetic field, and a UHECR composition compatible with the current expectations. We have used the Jansson-Farrar JF12 model for the Galactic magnetic field and an extragalactic magnetic field strength of 1nG and coherence length of 1Mpc. We observe that the regions outside of the Galactic plane are more strongly correlated with the neutrino tracks than those adjacent to or in it, with the former regions being good candidates to search for excesses, or anisotropies, in the UHECR flux. Additionally, we have focused, as an example, on the region of 150 EeV UHECR arrival directions correlated with the IceCube event 37 located at $(l,b)=(-137.1^\circ,65.8^\circ)$ in the Northern Hemisphere, far away from the Galactic plane, obtaining an angular size $\sim 5^\circ$, being $\sim 3^\circ$ for 200 EeV, and $\sim 8^\circ$ for 120 EeV. The results presented in this paper represent a useful UHECR excess search Sky map guide.