Parametrization of the angular distribution of Cherenkov light in air showers

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.

Cosmic-ray measurements by reconstructing longitudinal shower profiles for the Cherenkov Telescope Array

“…This process generates one photon profile per telescope. In the final step of the reconstruction, the electron profiles are obtained from the photons profiles using a parametrization for the angular distribution of Cherenkov light around the shower axis given by [10]:…”

“…The template-based analysis techniques require detailed and computing-intensive simulations of image templates for each array configuration and particle type while our method does not. Instead, our method uses a parameterized function that describes the development of the Cherenkov light along the air shower for gamma and cosmic rays separately [10]. For other techniques and resolution values (see [11,12]).…”