학술논문
Prototype Schwarzschild-Couder Telescope for the Cherenkov Telescope Array: Commissioning the Optical System
Document Type
Working Paper
Author
Adams, C. B.; Ambrosi, G.; Ambrosio, M.; Aramo, C.; Batista, P. I.; Benbow, W.; Bertucci, B.; Bissaldi, E.; Bitossi, M.; Boiano, A.; Bonavolontà, C.; Bose, R.; Brill, A.; Buckley, J. H.; Cameron, R. A.; Canestrari, R.; Capasso, M.; Caprai, M.; Covault, C. E.; Depaoli, D.; Di Venere, L.; Errando, M.; Fegan, S.; Feng, Q.; Fiandrini, E.; Furniss, A.; Gent, A.; Giglietto, N.; Giordano, F.; Giro, E.; Halliday, R.; Hervet, O.; Humensky, T. B.; Incardona, S.; Ionica, M.; Jin, W.; Kieda, D.; Licciulli, F.; Loporchio, S.; Marsella, G.; Masone, V.; Meagher, K.; Meures, T.; Mode, B. A. W.; Mognet, S. A. I.; Mukherjee, R.; Nieto, D.; Okumura, A.; Otte, N.; Pantaleo, F. R.; Paoletti, R.; Pareschi, G.; Di Pierro, F.; Pueschel, E.; Ribeiro, D.; Riitano, L.; Roache, E.; Rousselle, J.; Rugliancich, A.; Santander, M.; Shang, R.; Stiaccini, L.; Taylor, L. P.; Tosti, L.; Tovmassian, G.; Tripodo, G.; Vagelli, V.; Valentino, M.; Vandenbroucke, J.; Vassiliev, V. V.; Williams, D. A.; Yu, P.
Source
Proceedings of Science, PoS(ICRC2021)717
Subject
Language
Abstract
A prototype Schwarzschild-Couder Telescope (pSCT) has been constructed at the Fred Lawrence Whipple Observatory as a candidate for the medium-sized telescopes of the Cherenkov Telescope Array Observatory (CTAO). CTAO is currently entering early construction phase of the project and once completed it will vastly improve very high energy gamma-ray detection component in multi-wavelength and multi-messenger observations due to significantly improved sensitivity, angular resolution and field of view comparing to the current generation of the ground-based gamma-ray observatories H.E.S.S., MAGIC and VERITAS. The pSCT uses a dual aspheric mirror design with a $9.7$ m primary mirror and $5.4$ m secondary mirror, both of which are segmented. The Schwarzschild-Couder (SC) optical system (OS) selected for the prototype telescope achieves wide field of view of $8$ degrees and simultaneously reduces the focal plane plate scale allowing an unprecedented compact ($0.78$m diameter) implementation of the high-resolution camera ($6$mm/ $0.067$deg per imaging pixel with $11,328$ pixels) based on the silicon photo-multipliers (SiPMs). The OS of the telescope is designed to eliminate spherical and comatic aberrations and minimize astigmatism to radically improve off-axis imaging and consequently angular resolution across all the field of view with respect to the conventional single-mirror telescopes. Fast and high imaging resolution OS of the pSCT comes with the challenging submillimeter-precision custom alignment system, which was successfully demonstrated with an on-axis point spread function (PSF) of $2.9$ arcmin prior to the first-light detection of the Crab Nebula in 2020. Ongoing and future commissioning activities are reported.