Observations of the Crab Nebula and Pulsar with the Large-sized Telescope Prototype of the Cherenkov Telescope Array

Abe, H.; Abe, K.; Abe, S.; Aguasca-Cabot, A.; Agudo, I.; Crespo, N. A.; Antonelli, L. A.; Aramo, C.; Arbet-Engels, A.; Arcaro, C.; Artero, M.; Asano, K.; Aubert, P.; Baktash, A.; Bamba, A.; Larriva, A. B.; Baroncelli, L.; de Almeida, U. B.; Barrio, J. A.; Batkovic, I.; Baxter, J.; Gonzalez, J. B.; Bernardini, E.; Bernardos, M. I.; Medrano, J. B.; Berti, A.; Bhattacharjee, P.; Biederbeck, N.; Bigongiari, C.; Bissaldi, E.; Blanch, O.; Bonnoli, G.; Bordas, P.; Borghese, A.; Bulgarelli, A.; Burelli, I.; Buscemi, M.; Cardillo, M.; Caroff, S.; Carosi, A.; Cassol, F.; Cauz, D.; Ceribella, G.; Chai, Y.; Cheng, K.; Chiavassa, A.; Chikawa, M.; Chytka, L.; Cifuentes, A.; Contreras, J. L.; Cortina, J.; Costantini, H.; D'Amico, G.; Dalchenko, M.; De Angelis, A.; de Bony de Lavergne, M.; De Lotto, B.; de Menezes, R.; Deleglise, G.; Delgado, C.; Delgado Mengual, J.; Volpe, D. D.; Dellaiera, M.; Depaoli, D.; Di Piano, A.; Di Pierro, F.; Di Tria, R.; Di Venere, L.; Diaz, C.; Dominik, R. M.; Prester, D. D.; Donini, A.; Dorner, D.; Doro, M.; Elsasser, D.; Emery, G.; Escudero, J.; Ramazani, V. F.; Ferrara, G.; Ferrarotto, F.; Fiasson, A.; Coromina, L. F.; Frose, S.; Fukami, S.; Fukazawa, Y.; Garcia, E.; Garcia Lopez, R.; Gasbarra, C.; Gasparrini, D.; Geyer, F.; Paiva, J. G.; Giglietto, N.; Giordano, F.; Giro, E.; Gliwny, P.; Godinovic, N.; Grau, R.; Green, D.; Green, J.; Gunji, S.; Hackfeld, J.; Hadasch, D.; Hahn, A.; Hashiyama, K.; Hassan, T.; Hayashi, K.; Heckmann, L.; Heller, M.; Llorente, J. H.; Hirotani, K.; Hoffmann, D.; Horns, D.; Houles, J.; Hrabovsky, M.; Hrupec, D.; Hui, D.; Hutten, M.; Iarlori, M.; Imazawa, R.; Inada, T.; Inome, Y.; Ioka, K.; Iori, M.; Ishio, K.; Iwamura, Y.; Jacquemont, M.; Martinez, I. J.; Jurysek, J.; Kagaya, M.; Karas, V.; Katagiri, H.; Kataoka, J.; Kerszberg, D.; Kobayashi, Y.; Kong, A.; Kubo, H.; Kushida, J.; Lainez, M.; Lamanna, G.; Lamastra, A.; Le Flour, T.; Linhoff, M.; Longo, F.; Lopez-Coto, R.; Lopez-Moya, M.; Lopez-Oramas, A.; Loporchio, S.; Lorini, A.; Luque-Escamilla, P. L.; Majumdar, P.; Makariev, M.; Mandat, D.; Manganaro, M.; Manico, G.; Mannheim, K.; Mariotti, M.; Marquez, P.; Marsella, G.; Marti, J.; Martinez, O.; Martinez, G.; Martinez, M.; Marusevec, P.; Mas-Aguilar, A.; Maurin, G.; Mazin, D.; Guillen, E. M.; Micanovic, S.; Miceli, D.; Miener, T.; Miranda, J. M.; Mirzoyan, R.; Mizuno, T.; Gonzalez, M. M.; Molina, E.; Montaruli, T.; Monteiro, I.; Moralejo, A.; Morcuende, D.; Morselli, A.; Mrakovcic, K.; Murase, K.; Nagai, A.; Nagataki, S.; Nakamori, T.; Nickel, L.; Nievas, M.; Nishijima, K.; Noda, K.; Nosek, D.; Nozaki, S.; Ohishi, M.; Ohtani, Y.; Oka, T.; Okazaki, N.; Okumura, A.; Orito, R.; Otero-Santos, J.; Palatiello, M.; Paneque, D.; Pantaleo, F. R.; Paoletti, R.; Paredes, J. M.; Pech, M.; Pecimotika, M.; Peresano, M.; Perez, A.; Pietropaolo, E.; Pirola, G.; Plard, C.; Podobnik, F.; Poireau, V.; Polo, M.; Pons, E.; Prandini, E.; Prast, J.; Principe, G.; Priyadarshi, C.; Prouza, M.; Rando, R.; Rhode, W.; Ribo, M.; Rizi, V.; Fernandez, G. R.; Ruiz, J. E.; Saito, T.; Sakurai, S.; Sanchez, D. A.; Saric, T.; Sato, Y.; Saturni, F. G.; Schleicher, B.; Schmuckermaier, F.; Schubert, J. L.; Schussler, F.; Schweizer, T.; Arroyo, M. S.; Silvia, R.; Sitarek, J.; Sliusar, V.; Spolon, A.; Striskovic, J.; Strzys, M.; Suda, Y.; Sunada, Y.; Tajima, H.; Takahashi, H.; Takahashi, M.; Takata, J.; Takeishi, R.; Tam, P. H. T.; Tanaka, S. J.; Tateishi, D.; Tejedor, L. A.; Temnikov, P.; Terada, Y.; Terauchi, K.; Terzic, T.; Teshima, M.; Tluczykont, M.; Tokanai, F.; Torres, D. F.; Travnicek, P.; Truzzi, S.; Tutone, A.; Uhlrich, G.; Vacula, M.; Vallania, P.; van Scherpenberg, J.; Acosta, M. V.; Verguilov, V.; Viale, I.; Vigliano, A.; Vigorito, C. F.; Vitale, V.; Voutsinas, G.; Vovk, I.; Vuillaume, T.; Walter, R.; Will, M.; Yamamoto, T.; Yamazaki, R.; Yoshida, T.; Yoshikoshi, T.; Zywucka, N.; Bernlohr, K.; Gueta, O.; Kosack, K.; Maier, G.; Watson, J.

doi:10.3847/1538-4357/ace89d

The Cherenkov Telescope Array (CTA) is a next-generation ground-based observatory for gamma-ray astronomy at very high energies. The Large-Sized Telescope prototype (LST-1) is located at the CTA-North site, on the Canary Island of La Palma. LSTs are designed to provide optimal performance in the lowest part of the energy range covered by CTA, down to ≃20 GeV. LST-1 started performing astronomical observations in 2019 November, during its commissioning phase, and it has been taking data ever since. We present the first LST-1 observations of the Crab Nebula, the standard candle of very-high-energy gamma-ray astronomy, and use them, together with simulations, to assess the performance of the telescope. LST-1 has reached the expected performance during its commissioning period—only a minor adjustment of the preexisting simulations was needed to match the telescope’s behavior. The energy threshold at trigger level is around 20 GeV, rising to ≃30 GeV after data analysis. Performance parameters depend strongly on energy, and on the strength of the gamma-ray selection cuts in the analysis: angular resolution ranges from 0.°12-0.°40, and energy resolution from 15%-50%. Flux sensitivity is around 1.1% of the Crab Nebula flux above 250 GeV for a 50 hr observation (12% for 30 minutes). The spectral energy distribution (in the 0.03-30 TeV range) and the light curve obtained for the Crab Nebula agree with previous measurements, considering statistical and systematic uncertainties. A clear periodic signal is also detected from the pulsar at the center of the Nebula.