The CoMET multiperspective event tracker for wide field-of-view gamma-ray astronomy

TL;DR

The CoMET project develops a multiperspective ground-based gamma-ray observatory combining particle and Cherenkov detectors at high altitude to improve detection and reconstruction of very high-energy gamma-ray sources.

Contribution

This paper introduces the design, simulation, and expected performance of the CoMET multiperspective detector array for VHE gamma-ray astronomy, integrating particle and Cherenkov detection methods.

Findings

Simulations show improved gamma-ray shower reconstruction accuracy.

The combined detector approach enhances background discrimination.

Prototype detectors are operational at Linnaeus University.

Abstract

The CoMET R&D project focuses on the development of a new technique for the observation of very high-energy (VHE) $\gamma$-rays from the ground at energies above ~200 GeV, thus covering emission from soft-spectrum sources. The CoMET array under study combines 1242 particle detector units, distributed over a circular area of ~160 m in diameter and placed at a very high altitude (5.1 km), with atmospheric Cherenkov light detectors. The atmospheric Cherenkov light detectors, inspired by the "HiSCORE" design and improved for the energy range of interest, can be operated together with the particle detectors during clear nights. As such, the instrument becomes a Cosmic Multiperspective Event Tracker (CoMET). CoMET is expected to improve the reconstruction of arrival direction, energy and shower maximum determination for $\gamma$-ray-induced showers during darkness, which is crucial for the reduction of background contamination from cosmic rays. Prototypes of both particle and atmospheric Cherenkov light detectors are already installed at Linnaeus University in Sweden, while in parallel we simulate the full detector response and estimate the reconstruction improvement for $\gamma$-ray events. In this contribution, we present Monte-Carlo simulations of the detector array, consisting of CORSIKA shower simulations and custom detector response simulations, together with the coupling of particle and atmospheric Cherenkov light information, the reconstruction strategy of the complete array and the detection performance on point-like VHE $\gamma$-ray sources.