The Nuclear Window to the Extragalactic Universe

TL;DR

This study compares two models of the galactic magnetic field to understand their effects on cosmic nuclei trajectories, focusing on deflections, image multiplicity, and field transparency, with implications for cosmic ray source detection.

Contribution

It provides a comprehensive analysis of how different galactic magnetic field models affect cosmic ray propagation and detection strategies.

Findings

Deflections depend on energy and charge, with a rigidity threshold of 6 EV for ballistic trajectories.

Field uncertainties significantly impact source detection near the galactic disk.

Differences between models suggest the need to revise rigidity thresholds for accurate cosmic ray analysis.

Abstract

We investigate two recent parameterizations of the galactic magnetic field with respect to their impact on cosmic nuclei traversing the field. We present a comprehensive study of the size of angular deflections, dispersion in the arrival probability distributions, multiplicity in the images of arrival on Earth, variance in field transparency, and influence of the turbulent field components. To remain restricted to ballistic deflections, a cosmic nucleus with energy E and charge Z should have a rigidity above E/Z=6 EV. In view of the differences resulting from the two field parameterizations as a measure of current knowledge in the galactic field, this rigidity threshold may have to be increased. For a point source search with E/Z>60 EV, field uncertainties increase the required signal events for discovery moderately for sources in the northern and southern regions, but substantially for sources near the galactic disk.