Parametrization of the angular distribution of Cherenkov light in air showers

TL;DR

This paper introduces a new parametrization for the angular distribution of Cherenkov light in air showers, covering both small and large angles, which enhances the accuracy of shower reconstruction in gamma-ray and cosmic-ray observatories.

Contribution

A physically-motivated parametrization of Cherenkov light angular distribution that improves upon previous models for both small and large angles.

Findings

Provides a new parametrization constrained by simulations of gamma-ray and proton showers.

Enhances the precision of shower reconstruction in Cherenkov and fluorescence detectors.

Applicable across a wide energy range from TeV to EeV.

Abstract

The Cherenkov light produced in air showers largely contributes to the signal observed in ground-based gamma-ray and cosmic-ray observatories. Yet, no description of this phenomenon is available covering both regions of small and large angles to the shower axis. To fill this gap, a parametrization of the angular distribution of Cherenkov photons is performed in terms of a physically-motivated parametric function. Model parameters are constrained using simulated gamma-ray and proton showers with energies in the TeV to EeV region. As a result, a new parametrization is obtained that improves the precision of previous works. Results presented here can be used in the reconstruction of showers with imaging Cherenkov telescopes as well as in the reconstruction of shower profiles with fluorescence detectors.