Characterisation of the Atmosphere in Very High Energy Gamma-Astronomy for Imaging Atmospheric Cherenkov Telescopes
Dominis Prester, D. (University of Rijeka)
Ebr, Jan (Institute of Physics of the Czech Academy of Sciences)
Gaug, Markus (Universitat Autònoma de Barcelona. Departament de Física)
Hahn, Alexander (Max Planck Institut fuer Physik)
Babić, Ana (Faculty of Electrical Engineering and Computing. University of Zagreb)
Eliášek, Jiří (Institute of Physics of the Czech Academy of Sciences)
Janeček, Petr (Institute of Physics of the Czech Academy of Sciences)
Karpov, Sergey (Institute of Physics of the Czech Academy of Sciences)
Kolarek, Marta (University of Rijeka)
Manganaro, Marina (University of Rijeka)
Mirzoyan, Razmik (Max Planck Institut fuer Physik)

Date:	2024
Abstract:	Ground-based observations of Very High Energy (VHE) gamma rays from extreme astrophysical sources are significantly influenced by atmospheric conditions. This is due to the atmosphere being an integral part of the detector when utilizing Imaging Atmospheric Cherenkov Telescopes (IACTs). Clouds and dust particles diminish atmospheric transmission of Cherenkov light, thereby impacting the reconstruction of the air showers and consequently the reconstructed gamma-ray spectra. Precise measurements of atmospheric transmission above Cherenkov observatories play a pivotal role in the accuracy of the analysed data, among which the corrections of the reconstructed energies and fluxes of incoming gamma rays, and in establishing observation strategies for different types of gamma-ray emitting sources. The Major Atmospheric Gamma Imaging Cherenkov (MAGIC) telescopes and the Cherenkov Telescope Array Observatory (CTAO), both located on the Observatorio del Roque de los Muchachos (ORM), La Palma, Canary Islands, use different sets of auxiliary instruments for real-time characterisation of the atmosphere. In this paper, historical data taken by MAGIC LIDAR (LIght Detection And Ranging) and CTAO FRAM (F/Photometric Robotic Telescope) are presented. From the atmospheric aerosol transmission profiles measured by the MAGIC LIDAR and CTAO FRAM aerosol optical depth maps, we obtain the characterisation of the clouds above the ORM at La Palma needed for data correction and optimal observation scheduling.
Grants:	Agencia Estatal de Investigación PID2022-139117NB-C43 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-00607
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Atmospheric effects ; Gamma-ray astrophysics ; Active galactic nuclei ; Very high energy gamma rays ; Non-thermal ; High energy astrophysics
Published in:	Universe, Vol. 10, Issue 9 (September 2024) , art. 349, ISSN 2218-1997

DOI: 10.3390/universe10090349

17 p, 921.5 KB

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