PoS(ICRC2021)788 International 4 th 12–23 July 2021 July 12–23 37 SICS CONFERENCE SICS CONFERENCE Berlin | Germany Berlin Berlin | Germany Cosmic Ray Conference Ray Cosmic ICRC 2021 THE ASTROPARTICLE PHY ICRC 2021 THEASTROPARTICLE PHY on behalf of https://pos.sissa.it/ Lara Nava, 6,ℎ 3 ONLINE Yusuke Suda, 2 . This makes GRB 201216C the 1 . 1 = and Francesco Longo I 0 Serena Loporchio, 1 Katsuaki Asano 5 † Alessio Berti, ∗ 0, Željka Bošnjak, 0 [email protected] International Cosmic Ray Conference (ICRC 2021) a complete list of the MAGIC Collaboration authors can be found at the end of the proceedings Presenter ∗ † th most distant object ever detected by ground-basedwill gamma-ray show telescopes. the analysis In results this of contribution the we the MAGIC data, same also energy in range. comparison with Finally, accounting pastcomment detected for on GRBs available the multi-wavelength in possible observations, origin we of will the VHE emission detected by MAGIC. University of Trieste, Department of Physics, viaINFN, Valerio Sezione 2, di Trieste, Italy Trieste, via Valerio 2, Trieste, Italy E-mail: Gamma-ray bursts (GRBs) are the mostGRB physics energetic are phenomena still in under debate, the such Universe. asenergy the range. Many origin aspects of In their of 2019, gamma-ray emission MAGIC aboveemission detected the can GeV TeV gamma be rays well from explained theHowever, by long it is synchrotron-self GRB still Compton 190114C, unclear emission whose whether such by aof relativistic process GRBs electrons. is common detected in until GRBs, now given at theis reduced the the number very second high one energies detected (VHE). by GRBSwift-BAT, MAGIC MAGIC in 201216C automatically this is slewed to energy a range. the long GRB GRB Afterafter position, receiving and the starting the GRB observations alert onset. 56 provided seconds by Ingamma-ray the emission offline with analyses a of the significancefacilities, collected above the 5 data, we redshift sigma. confirmed of the Following this measurements detection GRB of from was optical estimated to be Institute for Cosmic Ray Research, The UniversityMax of Planck Tokyo, Institut Kashiwanoha for 5-1-5, Physics,Föhringer Kashiwa, Ring Japan 6,INFN Munich, MAGIC Germany Group: INFN Sezione diPolitecnico di Bari Bari, and I-70125, Dipartimento Bari, Interateneo Italy di FisicaPhysics dell’Università Program, e Graduate School del of Advanced Science739-8526 and Hiroshima, Japan Engineering, Hiroshima University, National Institute for Astrophysics (INAF), Street number,Faculty Merate, of Italy Electrical Engineering and Computing, University of Zagreb, Zagreb, Croatia Copyright owned by the author(s) under the terms of the Creative Commons 4 2 6 ℎ 0 1 3 5 © Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND 4.0). 37 July 12th – 23rd, 2021 Online – Berlin, Germany Koji Noda, the MAGIC Collaboration Satoshi Fukami, Very-high-energy gamma-ray emission from GRB 201216C detected by MAGIC PoS(ICRC2021)788 [11]. in the 9 s 20 s . + 29 0 ) Satoshi Fukami -BAT analysis, and -BAT at 23:07:31 UT on December Swift Swift , and the main peak occurred at 2 64 s + 0 ) )[].10 The light curve of the prompt emission consists 0 ) and 16 s − 0 ) as measured in the 15-350 keV band by s ) 16 ± 48 ( Gamma-ray bursts (GRBs) are the most powerful phenomena in the Universe emitting elec- The emission from GRBs is classified into two succeeding phases. The initial emission is The current accepted model of the afterglow explains the multiwavelength emission as syn- On January 14th, 2019, MAGIC detected for the first time a GRB in the very-high-energy In this work, we report the MAGIC observation and the analysis result of GRB 201216C, which GRB 201216C is a bright long GRB triggered by the is 90 16th, 2020 (from hereof on multiple denoted peaks as between tromagnetic radiation. Even thoughaspects, more such than 50 as years thegamma-ray have emission origin passed mechanism since of are their yet their to discovery, be prompt many properly emission, understood. the formationcalled of prompt relativistic emission, which jets, isof and dominated the the by flux. soft gamma Dependingclassification rays which on is and the related shows duration to irregular ofphase, the variability which different this may overlap progenitor with phase, systems the GRBs prompt producing emission,by the are is a GRB. called categorized afterglow. broadband The as This second emission phase long is from characterized months) or radio and short, to typical temporal gamma a decay rays following with a long simple power-law. lasting duration (fromchrotron few radiation days from to relativistic electrons, whichwhen are it accelerated interacts by the with forward the shockreverse interstellar of shock medium the is and jet decelerates also (e.g. evidentthe in multiwavelength [1]). spectra many A and cases contribution light (e.g.segments from curves with the are [2]). different expected indices. to As Observations be are a described in consequence general by agreement of multiple with this power-law this(VHE, simple scenario. model, roughly >50 GeV)detected range. from the Hundreds long-duration GRB of 190114Cthan gamma the [4]. maximum rays The energy between achievable emission by reached 300 synchrotronconsidered, photon emission suggesting GeV when energies the and presence standard higher of shock 1 an acceleration additional is TeV component.component were is The need also for an supported additional by spectral MAGIC the simultaneous double-bump observations shaped [5]. SED, Even as thoughwas constrained found a to by synchrotron be X-ray, able self-Compton LAT to and (SSC) explain emission thethat emission the from GRB SSC 190114C emission in the is VHEalso energetically range, detected it relevant is two among not GRBs all obvious in theone, the GRBs. GRB 190829A, VHE a The range difficulty H.E.S.S. several in Collaboration hoursbeen the interpretation claimed after (but of the the see triggers VHE [8]). observations [6,7]. Themany as data aspects SSC For of radiation such the the has as GRBs second observation detectedin time by the MAGIC after and VHE triggers H.E.S.S energies and have are variety energetics. thereforethe in necessary very More to high observations establish energy of component. a GRBs standard model explaining the origin of is the second GRB detected by MAGIC, on December 16th, 2020 [9]. 2. GRB 201216C MAGIC GRB 201216C 1. Introduction ) PoS(ICRC2021)788 2 + 10 15 . . 0 0 0 50 s cm ) + − / + 07 0 . erg ) 1 5 -GBM. − − and 10 away from the . The MAGIC and 0 Satoshi Fukami Fermi ) ) × 10 16 1 [15]. The duration . . . 17 m 0 0 4 deg 0 + − . 0 -XRT, starting at ± 09 bands respectively, and . 5 0 , a low energy index of . 2 1000 s 4 − in the 10-1000 keV band is ,I ( Swift + 0 0 keV is iso ) ,A ) 0  7 6 ± 9078 s 326 + ( to around 0 by the optical observations with the ESO ) . The observation was performed with the 6 s 1 . The fluence is . . in the Sloan 1 of exposure in total. The zenith angle ranged 56 s 03 31 . s = + 0 + 2 h 0 I 0 . 3 ± ) ) 2 . The robotic telescope FRAM-ORM automatically 25 . 05 2 . − 0 ± in the Roque de los Muchachos Observatory on the Canary [16]. The optical flux shows a peak around this time. 81 . in the 15-150 keV and in the 10-1000 keV bands respectively. 2 21 2200 m observation [18]. 177 s cm / + -GBM]. [12 The time-integrated spectrum between 1 h 0 . erg ) 0 calculated from the redshift and the fluence measured by band is 4 0 with the energy threshold increasing accordingly. Due to the absence of − A Fermi erg 10 53 band at ) × 0 10 68 deg A 06 . , and a high energy index of to ) × 0 [14]. The exposures were 120, 90, 180 01 ± 16 . . 0 . The power-law decay index before and after 0 41 19 h ± . . ± 37 deg 8 s 1 -BAT and started fast repositioning of the telescopes immediately [9]. MAGIC succeeded to . 2 The analysis of the data was performed with MAGIC Analysis and Reconstruction Software, Due to the large size of the telescopes, MAGIC can detect dim Cherenkov light, which At 23:07:51 UT on December 16th 2020, MAGIC received the alert of GRB 201216C from MAGIC consists of two imaging Cherenkov telescopes with a diameter of X-ray observations of the late-time afterglow were performed by Optical measurements were performed by several instruments. The ESO VLT detected the The redshift of this GRB is estimated to be ( 06 71 . + . 1 0 4 ( MARS [19]. Since gamma rays with energies above a few hundred GeV are strongly attenuated the moon, the level of thetherefore night obtain a sky low background energy was threshold. low enough to retain dim shower images and from so-called wobble mode, where the telescopes were pointed to a sky position source position. The MAGIC observation was leads to a relatively low energyMoreover, threshold the compared very to light other ground-based carbonso gamma-ray fiber that telescopes. structure MAGIC can allowsprocedure to start perform is observations fast of automatically rotation transient startedGRBs of phenomena as are the with received. soon telescopes short as delay. alerts of The immediately follow-up observableSwift sources such as start the observation with a stable trigger rate at respectively [17]. 3. MAGIC observation and analysis site is located at an altitudeIsland of of La Palma inrange Spain. where The gamma-ray target satellites energy doespecially range for not is bright from transient have sources. 50 high The GeV sensitivities.Crab to integral Nebula sensitivity 50 assuming above MAGIC TeV 105 a covering has GeV a is a 40% wide of high the sensitivity flux of reacted to the alert and observed thecovered the GRB onset from of the afterglow anddata the power-law temporal combined decay with index is the -1.07 VLT. estimated Theof by 18.38 Liverpool the in Telescope the (LT) reported detection with a magnitude 2966 the AB magnitude of afterglow by the observation of one of the telescopes (UT3) with X-shooter spectrograph starting and Very Large Telescope (VLT) [13]. The isotropic equivalent energy − MAGIC GRB 201216C 50-300 keV band by is best fitted by a Band function with a peak energy of ) PoS(ICRC2021)788 Satoshi Fukami (one data run) and -XRT. There is a spot of the source, the energy 20 min -XRT. The OFF regions are 1 Swift . 1 ∼ Swift I 4 of the MAGIC observation is shown in1. Fig. This . Taking into account a trial number of 2, the post-trial 20 min 20 min for the first f , which indicates the clear detection of the VHE emission from the GRB.2 Fig. f at the position consistent with the GRB within the PSF size. Distribution of angular distances between the reconstructed positions and the source position f , and obtained 6.0 The so-called theta2 plot for the first 2 h . Figure 1: (theta2 plot). The countsgrey. of The ON significance and is calculated OFF from regions the are counts inside plotted the together. dotted vertical The line OFF with Eq. distribution 17 is in filled LiMa with 1983. plot contains the distribution ofgamma-like squared events and angular the distances source position. between the Suchwithout a reconstructed any distribution positions was gamma-ray of also produced sources aroundposition. positions and The assumed overlapped source to position is compare taken from it the with report by the one around the source 4. Results distribution of the excess counts isTherefore, concentrated to at energies keep close as to many theto low-energy threshold events around extract as 100 possible, dimmer GeV. we Cherenkov adoptedusing showers an simulated initiated image events, we cleaning by confirmed method that gammasensitivity more below rays low-energy 100 events than GeV survived was the the improved with event standard this cuts method. and method. the By selected so that their centersposition. are at We the selected same in distanceobtained total from by 5 the averaging OFF and center normalizing regions of the andformula the counts. Eq. camera the as theta2 The 17 the signal distribution in source significance of Li&Ma2 is 1983 the calculated [20]. OFF using regions We the tried was significance two is analysis 5.9 periods of shows a significance sky mapabove 6 around the GRB position reported by MAGIC GRB 201216C by the extragalactic background light (EBL) given the redshift PoS(ICRC2021)788 . The 2 h . 2 + 0 Satoshi Fukami ) . The observed to -XRT (open cross). The 56 s at the GRB position by 20 min + f Swift 0 ) since we do not have significant excess after 5 50 min + 0 ) , making the source the second GRB detected by MAGIC. The 20 min . We detected VHE gamma rays with a significance above 5 , especially for the events with energies higher than a few hundreds of GeV. We then Test statistics map around the position of GRB 201216C reported by 1 . 1 56 s + ∼ MAGIC observed GRB 201216C immediately after receiving the alert and started observations We produced a preliminary time-integrated spectrum for the first Finally, we produced a preliminary photon-flux light curve from 0 I ) photon flux is monotonicallyUpper decaying limits with are derived time, for and the bins the after curve is consistent with a power-law. the offline analysis of the first excess counts are dominated by eventsBoth around the 100 observed and GeV, and EBL-corrected the spectra observed are spectrum compatible with is power-law very functions. steep. at that time. 5. Discussion and Conclusions calculated the EBL-corrected spectrum using[21]). the . EBL model The by EBL-corrected Dominguez spectralaround energy 2011 distribution 100 (hereafter is D11 consistent GeV, too. with a flatterexcess We single counts power-law have due no to the spectral strong points flux attenuation. above 200 GeV since there are no significant Figure 2: PSF size is shown with the white circle. spectrum has a very steepof power-law index due to the strong attenuation by EBL from a distance MAGIC GRB 201216C PoS(ICRC2021)788 https:// Satoshi Fukami -ray burst. Nature, W -ray burst afterglow. Nature, W -ray burst GRB 190114C. Nature, W 6 190829A afterglow. Science, 372:1081-1085, Jun. 2021 gamma-ray burst physics, arXiv:2106.07169, 2021. 575:455–458, Nov. 2019. 575:459–463, Nov. 2019. 575:464–467, Nov. 2019. 812, Dec. 2000 561:1-109, Feb. 2015. We found that the MAGIC flux decays monotonically with time and is consistent with a power- The temporal and spectral behaviour of the VHE emission detected from GRB 201216C are We acknowledge the support from the agencies and organizations listed here: [7] H. Abdalla et al. A very-high-energy component deep in the [9] O. Blanch et al. GCN Circular 29075, Dec. 2020. [5] V.A. Acciari et al. Observation of inverse Compton emission from a long [6] H. Abdalla et al. Revealing x-ray and gamma ray temporal and spectral similarities in the GRB [8] O. S. Salafia et al., Multi-wavelength view of the close-by GRB 190829A sheds light on [3] O. Blanch et al. GCN Circular 29075,[4] Dec. 2020. V.A. Acciari et al. Teraelectronvolt emission from the [2] S. Kobayashi. Light curves of gamma-ray burst optical flashes. Astrophysical Journal, 545:807- [1] P. Kumar and B. Zhang. The physics of gamma-ray bursts & relativistic jets. Physics Reports, [10] A. P. Beardmore et al. GCN Circular[11] 29061, Dec.T. 2020. N. Ukwatta et al. GCN Circular 29080,[12] Dec. 2020. C. Malacaria et al. GCN Circular 29073, Dec. 2020. law. The timescale oforigin the of MAGIC the emission VHE and radiation is the related temporal to behaviour the let afterglow phase. usqualitatively conclude similar that to the those ofstudy of the MWL emission data detected isexplained from needed in GRB to 190114C. terms understand of However, if a SSC alsoperformed detailed radiation. in to this test Currently, case the whether the modeling theincluding emission of synchrotron MAGIC. can the + The be MWL SSC results satisfactorily observations scenario ofCollaboration, is can in this being preparation). explain study the will multiwavelength be data the subject of anAcknowledgements upcoming paper (MAGIC MAGIC GRB 201216C magic.mpp.mpg.de/acknowledgments_ICRC2021 References PoS(ICRC2021)788 , , , , , , , , , , , , , , , , , , , , 2 6 3 3 9 5 9 1 8 1 2 5 3 1 22 11 12 17 40 24 25 ETH 4 , U. Bar- 9 , T. Saito , L. Nava , S. Paiano , L. Jouvin , G. Vanzo 28 , T. Miener 35 1 , Ž. Bošnjak , J. Herrera 25 15 49 , B. De Lotto , F. Tavecchio , N. Giglietto 16 15 , , E. Colombo , E. Lindfors 6 2 5 , B. Machado de , T. Yamamoto 3 11 Croatian MAGIC 26 , M. Bernardos , M. V. Fonseca , K. Mannheim , D. Sobczynska 7 22 13 8 14 23 37 Satoshi Fukami , A. Baquero IPARCOS Institute and 8 , P. G. Prada Moroni 9 15 , N. Sahakyan , E. Do Souto Espiñeira , T. Nakamori , M. Gaug , G. Bonnoli , D. Miceli , F. Leone 5 , R. Takeishi 7 17 22 28 6 23 29 , J. Otero-Santos , L. Heckmann , J. Jormanainen , S. M. Colak , A. Fattorini 31 , I. Šnidarić 8 , A. Babić , A. De Angelis 15 20 , S. Loporchio 45 7 3 12 , E. Bernardini , C. Wunderlich , 1 , M. Pihet , M. Manganaro 13 15 25 50 , J. van Scherpenberg , 34 2 26 , E. Moretti , T. Oka , D. Lelas 6 3 26 , S. Cikota , S. Gasparyan , A. Hahn , F. Dazzi , D. Baack , M. Takahashi , S. Mićanović , L. Di Venere , J. Sitarek , H. Bökenkamp 6 6 , M. Will , A. Rugliancich 7 19 14 43 Centro Brasileiro de Pesquisas Físicas (CBPF), 5 6 37 3 , 21 15 , L. Bellizzi 17 10 , M. Persic , S. Ubach 12 9 , G. Maneva 3 , Y. Ohtani 11 , A. López-Oramas 31 , V. Moreno , I. Vovk , I. Jiménez Martínez 9 9 , T. Surić , K. Asano , A. Lamastra 6 , C. Righi 39 5 , O. Blanch 5 , V. Fallah Ramazani , S. Mender 27 32 4 , D. Hadasch 7 , P. Peñil 13 , P. Da Vela , T. Schweizer 15 , F. Di Pierro 23 3 7 , M. Garczarczyk , A. Tutone 21 , A. Chilingarian 1 , W. Bednarek 13 15 , S. Nozaki 1 , J. Rico 6 , V. Vitale , Y. Suda 7 6 , M. Artero 18 21 , M. Mallamaci , A. Biland 4 , Y. Iwamura 3 , J. Kushida National Institute for Astrophysics (INAF), I-00136 Rome, Italy 34 12 , D. Morcuende , D. Green 3 , V. D’Elia , D. Elsaesser 31 5 3 , M. López-Moya , L. Pavletić , K. Schmidt , S. Menchiari 42 11 , Y. Chai 11 , 18 , K. Noda 24 , S. Truzzi 15 , D. Depaoli , 18 15 6 , M. Ribó 32 38 20 , M. Strzys 7 15 , K. Ishio 6 , H. Kubo , R. J. García López , C. F. Vigorito Japanese MAGIC Group: Institute for Cosmic Ray Research (ICRR), The University 6 , C. Bigongiari , M. Doro , M. Makariev 27 34 6 Technische Universität Dortmund, D-44221 Dortmund, Germany , A. Arbet Engels , A. Moralejo 14 , J. G. Green 24 , J. Becerra González 3 33 7 , L. Tosti 18 , D. Mazin 29 6 11 , , M. Cerruti 5 , J. M. Paredes , W. Rhode , B. Schleicher , D. Strom , G. D’Amico , R. López-Coto 15 15 3 , T. Inada 3 13 , K. Nishijima 29 Institut de Física d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology 30 47 15 , 25 5 2 , D. Dorner , V. Verguilov , Y. Fukazawa , Y. Kobayashi 2 , E. Molina 6 5 , C. Delgado Mendez 13 , I. Batković , P. Majumdar 15 9 , I. Puljak 44 , L. A. Antonelli , S. Covino 5 , 26 , R. Paoletti , M. Martínez , N. Godinović 5 , M. Teshima , W. Bhattacharyya 41 20 , F. G. Saturni , M. Hütten , F. Longo , G. Ceribella 15 , 11 , J. Strišković 12 , K. Nilsson 3 2 3 23 15 5 14 30 17 , A. Donini , S. Fukami , S. Ventura 23 1 15 , J. A. Barrio , D. Kerszberg , C. Maggio , R. Mirzoyan , J. Cortina 1 10 , J. Delgado , C. Nigro 9 , T. Terzić 10 13 , P. Gliwny , S. Ansoldi , D. Paneque , C. Priyadarshi , M. Mariotti , R. Carosi 44 1 36 2 , D. Hrupec 34 29 , 22 , A. Stamerra 3 , S. Lombardi 5 , K. Satalecka 11 11 46 7 6 11 , J. Besenrieder , , C. Fruck 9 15 using observations of the Crab Nebula. Astroparticle Physics, 72:76-94, Jan. 2016. July 2013 272:317-324, Sep. 1983 fractions. Monthly Notices of the Royal Astronomical Society, 410:2556–2578, Feb. 2011. 26 Instituto de Astrofísica de Canarias and Dpto. de Astrofísica, Universidad de La Laguna, E-38200, La Laguna, Tenerife, Spain E. Prandini M. Palatiello V. Neustroev J. M. Miranda M. Karjalainen F. Giordano J. Hoang L. Maraschi The MAGIC Collaboration V. A. Acciari MAGIC GRB 201216C [13] J. Vielfaure et al. GCN Circular 29077,[14] Dec. 2020 L. Izzo et al. GCN Circular 29066,[15] Dec. 2020 M. Jelinek et al. GCN Circular 29070,[16] Dec. 2020 M. Shrestha et al. GCN Circular 29085,[17] Dec. 2020 P. A. Evans et al. GCN Circular 29280,[18] Dec. 2020 J. Aleksic et al. The major upgrade of the MAGIC telescopes,[19] Part II:R. A Zanin performance et al. study Proceedings, 33rd International Cosmic Ray Conference (ICRC2013),[20] p2937 T. Li and Y. Ma. Analysis methods for results in gamma-ray astronomy. Astrophysical Journal, [21] A. Dominguez et al. Extragalactic background light inferred from AEGIS galaxy-SED-type res de Almeida A. Berti L. Font L. Linhoff G. Busetto J. L. Contreras M. Delfino D. Dominis Prester Oliveira Fraga S. Sakurai A. Spolon (BIST), E-08193 Bellaterra (Barcelona), Spain of Tokyo, Kashiwa, 277-8582 Chiba, Japan P. Temnikov and D. Zarić 1 Università di Udine and INFNZürich, Trieste, CH-8093 I-33100 Zürich, Udine, Switzerland Italy Group: University of Zagreb, Faculty ofEMFTEL Electrical Department, Engineering Universidad and Complutense Computing de (FER), Madrid, 10000 E-28040 Zagreb, Madrid, Croatia Spain M. Vazquez Acosta PoS(ICRC2021)788 47 Japanese Universität 31 24 Finnish MAGIC 36 Satoshi Fukami Università di Pisa and 17 Croatian MAGIC Group: Armenian MAGIC Group: 29 19 University of Lodz, Faculty of INFN MAGIC Group: INFN 12 39 now at Department for Physics and 42 also at Port d’Informació Científica (PIC), 44 Università di Siena and INFN Pisa, I-53100 Siena, Japanese MAGIC Group: Department of Physics, Max-Planck-Institut für Physik, D-80805 München, 13 Croatian MAGIC Group: Ruđer Bošković Institute, 32 15 37 now at Laboratoire d’Annecy de Physique des Particules 49 Centro de Investigaciones Energéticas, Medioambientales y 20 8 Saha Institute of Nuclear Physics, HBNI, 1/AF Bidhannagar, Salt Lake, also at INAF Trieste and Dept. of Physics and Astronomy, University of 33 now at University of Innsbruck 50 43 Università di Padova and INFN, I-35131 Padova, Italy 11 Finnish MAGIC Group: Finnish Centre for Astronomy with ESO, University of Turku, Japanese MAGIC Group: Department of Physics, Konan University, Kobe, Hyogo 658- 25 40 INFN MAGIC Group: INFN Sezione di Torino and Università degli Studi di Torino, I-10125 now at Ruhr-Universität Bochum, Fakultät für Physik und Astronomie, Astronomisches Institut now at Department of Astronomy, University of California Berkeley, Berkeley CA 94720 21 45 46 Inst. for Nucl. Research and Nucl. Energy, Bulgarian Academy of Sciences, BG-1784 Sofia, 34 Universitat de Barcelona, ICCUB, IEEC-UB, E-08028 Barcelona, Spain 18 Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain Croatian MAGIC Group: University of Rijeka, Department of Physics, 51000 Rijeka, Croatia INFN MAGIC Group: INFN Sezione di Perugia, I-06123 Perugia, Italy 26 23 38 Armenian MAGIC Group: ICRANet-Armenia at NAS RA, 0019 Yerevan, Armenia 28 also at International Center for Relativistic Astrophysics (ICRA), Rome, Italy INFN MAGIC Group: INFN Sezione di Bari and Dipartimento Interateneo di Fisica dell’Università e del Politecnico di 41 22 Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, 18008, Granada, Spain Japanese MAGIC Group: Department of Physics, Yamagata University, Yamagata 990-8560, Japan 16 35 Deutsches Elektronen-Synchrotron (DESY), D-15738 Zeuthen, Germany 14 Croatian MAGIC Group: Josip Juraj Strossmayer University of Osijek, Department of Physics, 31000 Osijek, Croatia Japanese MAGIC Group: Physics Program, Graduate School of Advanced Science and Engineering, Hiroshima University, 739-8526 Würzburg, D-97074 Würzburg, Germany University of Split, Faculty30 of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB), 21000 Split, Croatia 27 Hiroshima, Japan FI-20014 Turku, Finland MAGIC GRB 201216C 22290-180 URCA, Rio de Janeiro (RJ), Brazil Physics and Applied Informatics, Department of Astrophysics, 90-236 Lodz,Italy Poland Germany INFN Pisa, I-56126 Pisa, Italy A. Alikhanyan National Science Laboratory,Tecnológicas, E-28040 0036 Madrid, Yerevan, Spain Armenia Torino, Italy Bari, I-70125 Bari, Italy MAGIC Group: Department of Physics, KyotoTokai University, 606-8502 University, Kyoto, Hiratsuka, Japan 259-1292 Kanagawa, Japan Group: Astronomy Research Unit, University of10000 Oulu, Zagreb, FI-90014 Croatia Oulu, Finland Roma Tor Vergata, I-00133 Roma,8501, Italy Japan Technology, University of Bergen, NO-5020, Norway Bulgaria Sector-1, Kolkata 700064, India E-08193 Bellaterra (Barcelona), Spain also at Dipartimento di Fisica,(LAPP), Università di CNRS-IN2P3, Trieste, 74941 I-34127 Annecy Trieste, Italy Cedex, France (AIRUB), 44801 Bochum, Germany Bologna, Bologna, Italy