No Arabic abstract
Our Galaxy is filled with cosmic-ray particles and more than 98% of them are atomic nuclei. In order to clarify their origin and acceleration mechanism, chemical composition measurements of these cosmic rays with wide energy coverage play an important role. Imaging Atmospheric Cherenkov Telescope (IACT) arrays are designed to detect cosmic gamma-rays in the very-high-energy regime ($sim$TeV). Recently these systems proved to be capable of measuring cosmic-ray chemical composition in the sub-PeV region by capturing direct Cherenkov photons emitted by charged primary particles. Extensive air shower profiles measured by IACTs also contain information about the primary particle type since the cross section of inelastic scattering in the air depends on the primary mass number. The Cherenkov Telescope Array (CTA) is the next generation IACT system, which will consist of multiple types of telescopes and have a km$^2$-scale footprint and extended energy coverage (20 GeV to 300 TeV). In order to estimate CTA potential for cosmic ray composition measurement, a full Monte Carlo simulation including a description of extensive air shower and detector response is needed. We generated a number of cosmic-ray nuclei events (8 types selected from H to Fe) for a specific CTA layout candidate in the southern-hemisphere site. We applied Direct Cherenkov event selection and shower profile analysis to these data and preliminary results on charge number resolution and expected event count rate for these cosmic-ray nuclei are presented.
The SST-1M telescope was developed as a prototype of a Small-Size-Telescope for the Cherenkov Telescope Array observatory and it has been extensively tested in Krakow since 2017. In this contribution we present validation of the Monte Carlo model of the prototype and expected performance in Krakow conditions. We focus on gamma/hadron separation and mono reconstruction of energy and gamma photon arrival direction using Machine learning methods.
The Cherenkov Telescope Array (CTA) represents the next generation of ground based instruments for Very High Energy gamma-ray astronomy. It is expected to improve on the sensitivity of current instruments by an order of magnitude and provide energy coverage from 20 GeV to more than 200 TeV. In order to achieve these ambitious goals Monte Carlo (MC) simulations play a crucial role, guiding the design of CTA. Here, results of the second large-scale MC production are reported, providing a realistic estimation of feasible array candidates for both Northern and Sourthern Hemisphere sites performance, placing CTA capabilities into the context of the current generation of High Energy $gamma$-ray detectors.
The Cherenkov Telescope Array (CTA) is a future very high energy gamma-ray observatory. CTA will be comprised of small-,medium- and large-size telescopes covering an energy range from tens of GeV to hundreds of TeV and will surpass existing telescopes in sensitivity by an order of magnitude. The aim of our study is to find the optimal design for the medium-size telescopes (MSTs), which will determine the sensitivity in the key energy range between a few hundred GeV to about ten TeV. To study the effect of the telescope design parameters on the array performance, we simulated arrays of 61 MSTs with 120 m spacing and a variety of telescope configurations. We investigated the influence of the primary telescope characteristics including optical resolution, pixel size, and light collection area on the total array performance with a particular emphasis on telescope configurations with imaging performance similar to the proposed Davies-Cotton (DC) and Schwarzschild-Couder (SC) MST designs. We compare the performance of these telescope designs, especially the achieved gamma-ray angular resolution and differential point-source sensitivity. Finally we investigate the performance of different array sizes to demonstrate impacts of financial constraints on the number of telescopes.
The Cherenkov Telescope Array (CTA) is a future very high energy gamma-ray observatory. CTA will be comprised of small-, medium- and large-size telescopes covering an energy range from tens of GeV to hundreds of TeV and will surpass existing telescopes in sensitivity by an order of magnitude. The aim of our study is to find the optimal design for the medium-size telescopes (MSTs), which will determine the sensitivity in the key energy range between a few hundred GeV to about ten TeV. To study the effect of the telescope design parameters on the array performance, we simulated arrays of 61 MSTs with 120 m spacing and a variety of telescope configurations. We investigated the influence of the primary telescope characteristics including optical resolution, pixel size, and light collection area on the total array performance with a particular emphasis on telescope configurations with imaging performance similar to the proposed Davis-Cotton (DC) and Schwarzschild-Couder (SC) MST designs. We compare the performance of these telescope designs, especially the achieved gamma-ray angular resolution and differential point-source sensitivity.
We present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parameters including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies-Cotton (DC) and Schwarzchild-Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30-40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. We attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.