TY - JOUR
T1 - Performance of the Cherenkov Telescope Array in the presence of clouds
AU - the Cherenkov Telescope Array Consortium
AU - Pecimotika, Mario
AU - Adamczyk, Katarzyna
AU - Prester, Dijana Dominis
AU - Gueta, Orel
AU - Hrupec, Dario
AU - Maier, Gernot
AU - Mićanović, Saša
AU - Pavletić, Lovro
AU - Sitarek, Julian
AU - Sobczyńska, Dorota
AU - Szanecki, Michał
AU - Abdalla, H.
AU - Abe, H.
AU - Abe, S.
AU - Abusleme, A.
AU - Acero, F.
AU - Acharyya, A.
AU - Acín Portella, V.
AU - Ackley, K.
AU - Adam, R.
AU - Adams, C.
AU - Adhikari, S. S.
AU - Aguado-Ruesga, I.
AU - Agudo, I.
AU - Aguilera, R.
AU - Aguirre-Santaella, A.
AU - Aharonian, F.
AU - Alberdi, A.
AU - Alfaro, R.
AU - Alfaro, J.
AU - Alispach, C.
AU - Aloisio, R.
AU - Alves Batista, R.
AU - Amans, J. P.
AU - Amati, L.
AU - Amato, E.
AU - Ambrogi, L.
AU - Ambrosi, G.
AU - Ambrosio, M.
AU - Ammendola, R.
AU - Anderson, J.
AU - Anduze, M.
AU - Angüner, E. O.
AU - Antonelli, L. A.
AU - Antonuccio, V.
AU - Antoranz, P.
AU - Anutarawiramkul, R.
AU - Brisken, W.
AU - Fortson, L.
AU - Ribeiro, D.
N1 - Publisher Copyright:
© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0)
PY - 2022/3/18
Y1 - 2022/3/18
N2 - The Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed energies and spectra. This study presents the impact of various atmospheric conditions on CTA performance. The atmospheric transmission in a cloudy atmosphere in the wavelength range from 203 nm to 1000 nm was simulated for different cloud bases and different optical depths using the MODerate resolution atmospheric TRANsmission (MODTRAN) code. MODTRAN output files were used as inputs for generic Monte Carlo simulations. The analysis was performed using the MAGIC Analysis and Reconstruction Software (MARS) adapted for CTA. As expected, the effects of clouds are most evident at low energies, near the energy threshold. Even in the presence of dense clouds, high-energy gamma rays may still trigger the telescopes if the first interaction occurs lower in the atmosphere, below the cloud base. A method to analyze very high-energy data obtained in the presence of clouds is presented. The systematic uncertainties of the method are evaluated. These studies help to gain more precise knowledge about the CTA response to cloudy conditions and give insights on how to proceed with data obtained in such conditions. This may prove crucial for alert-based observations and time-critical studies of transient phenomena.
AB - The Cherenkov Telescope Array (CTA) is the future ground-based observatory for gamma-ray astronomy at very high energies. The atmosphere is an integral part of every Cherenkov telescope. Different atmospheric conditions, such as clouds, can reduce the fraction of Cherenkov photons produced in air showers that reach ground-based telescopes, which may affect the performance. Decreased sensitivity of the telescopes may lead to misconstructed energies and spectra. This study presents the impact of various atmospheric conditions on CTA performance. The atmospheric transmission in a cloudy atmosphere in the wavelength range from 203 nm to 1000 nm was simulated for different cloud bases and different optical depths using the MODerate resolution atmospheric TRANsmission (MODTRAN) code. MODTRAN output files were used as inputs for generic Monte Carlo simulations. The analysis was performed using the MAGIC Analysis and Reconstruction Software (MARS) adapted for CTA. As expected, the effects of clouds are most evident at low energies, near the energy threshold. Even in the presence of dense clouds, high-energy gamma rays may still trigger the telescopes if the first interaction occurs lower in the atmosphere, below the cloud base. A method to analyze very high-energy data obtained in the presence of clouds is presented. The systematic uncertainties of the method are evaluated. These studies help to gain more precise knowledge about the CTA response to cloudy conditions and give insights on how to proceed with data obtained in such conditions. This may prove crucial for alert-based observations and time-critical studies of transient phenomena.
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M3 - Conference article
AN - SCOPUS:85144605866
SN - 1824-8039
VL - 395
JO - Proceedings of Science
JF - Proceedings of Science
M1 - 763
T2 - 37th International Cosmic Ray Conference, ICRC 2021
Y2 - 12 July 2021 through 23 July 2021
ER -