Expected performance of the ALTO particle detector array designed for 200 GeV - 50 TeV gamma-ray astronomy

TL;DR

This paper evaluates the expected performance of the ALTO particle detector array, part of the CoMET gamma-ray observatory, focusing on its sensitivity to high-energy gamma-ray sources through detailed simulations and analysis.

Contribution

It provides a detailed simulation-based assessment of ALTO detector performance and sensitivity for VHE gamma-ray astronomy, highlighting its potential scientific capabilities.

Findings

ALTO detectors can effectively distinguish gamma-ray signals from cosmic-ray background.

The sensitivity analysis shows promising detection prospects for various astrophysical sources.

Simulation results support the feasibility of the CoMET observatory for high-energy gamma-ray observations.

Abstract

The CoMET is an R$\&$D project aiming to design a very-high-energy (VHE) gamma-ray observatory sensitive to energies above $\sim$ 200 GeV. The science goals include continuous observation of soft-spectrum VHE gamma-ray sources such as Active Galactic Nuclei (AGNs) and transients like Gamma-Ray Bursts (GRBs). With these objectives, CoMET is designed to have a low energy threshold with a wide field-of-view of about 2 sr, at a high altitude, and combines ALTO particle detectors with CLiC air-Cherenkov detectors. In this contribution, we focus on the ALTO particle detector array performance only. Water Cherenkov detectors are used for the detection of secondary particles in atmospheric air showers while scintillators serve as muon counters. A detailed study is presented through air-shower, detector and trigger simulations, followed by the reconstruction of the event parameters and the extraction of the signal (gamma-rays) from the background (cosmic-rays). We present the sensitivity of the ALTO detectors to a list of astrophysical sources using two SEMLA analysis configurations.