論文 - 奥村　曉

Multiwavelength study of the galactic PeVatron candidate LHAASO J2108+5157

Abe, S; Aguasca-Cabot, A; Agudo, I; Crespo, NA; Antonelli, LA; Aramo, C; Arbet-Engels, A; Artero, M; Asano, K; Aubert, P; Baktash, A; Bamba, A; Larriva, AB; Baroncelli, L; de Almeida, UB; Barrio, JA; Batkovic, I; Baxter, J; González, JB; Bernardini, E; Bernardos, MI; Medrano, JB; Berti, A; Bhattacharjee, P; Biederbeck, N; Bigongiari, C; Bissaldi, E; Blanch, O; Bordas, P; Buisson, C; 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, JL; Cortina, J; Costantini, H; D'Amico, G; Dalchenko, M; De Angelis, A; de Lavergne, MD; De Lotto, B; de Menezes, R; Deleglise, G; Delgado, C; Mengual, JD; della Volpe, D; Dellaiera, M; Di Piano, A; Di Pierro, F; Di Tria, R; Di Venere, L; Díaz, C; Dominik, RM; Prester, DD; Donini, A; Dorner, D; Doro, M; Elsässer, D; Emery, G; Escudero, J; Ramazani, VF; Ferrara, G; Fiasson, A; Coromina, LF; Fröse, S; Fukami, S; Fukazawa, Y; Garcia, E; López, RG; Gasparrini, D; Geyer, D; Paiva, JG; 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, JH; Hirotani, K; Hoffmann, D; Horns, D; Houles, J; Hrabovsky, M; Hrupec, D; Hui, D; Hütten, M; Imazawa, R; Inada, T; Inome, Y; Ioka, K; Iori, M; Ishio, K; Iwamura, Y; Jacquemont, M; Martinez, IJ; 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; López-Coto, R; López-Moya, M; López-Oramas, A; Loporchio, S; Lorini, A; Luque-Escamilla, PL; Majumdar, P; Makariev, M; Mandat, D; Manganaro, M; Manicò, G; Mannheim, K; Mariotti, M; Marquez, P; Marsella, G; Martí, J; Martinez, O; Martínez, G; Martínez, M; Marusevec, P; Mas-Aguilar, A; Maurin, G; Mazin, D; Guillen, EM; Micanovic, S; Miceli, D; Miener, T; Miranda, JM; Mirzoyan, R; Mizuno, T; Gonzalez, MM; Molina, E; Montaruli, T; Monteiro, I; Moralejo, A; Morcuende, D; Morselli, A; Mrakovcic, K; Murase, K; Nagai, A; Nakamori, T; Nickel, L; Nievas, M; Nishijima, K; Noda, K; Nosek, D; Nozaki, S; Ohishi, M; Ohtani, Y; Okazaki, N; Okumura, A; Orito, R; Otero-Santos, J; Palatiello, M; Paneque, D; Pantaleo, FR; Paoletti, R; Paredes, JM; Pavletic, L; Pech, M; Pecimotika, M; Pietropaolo, E; Pirola, G; Podobnik, F; Poireau, V; Polo, M; Pons, E; Prandini, E; Prast, J; Priyadarshi, C; Prouza, M; Rando, R; Rhode, W; Ribó, M; Rizi, V; Fernandez, GR; Saito, T; Sakurai, S; Sanchez, DA; Saric, T; Saturni, FG; Scherpenberg, J; Schleicher, B; Schmuckermaier, F; Schubert, JL; Schussler, F; Schweizer, T; Arroyo, MS; Sitarek, J; Sliusar, V; Spolon, A; Striskovic, J; Strzys, M; Suda, Y; Sunada, Y; Tajima, H; Takahashi, M; Takahashi, H; Takata, J; Takeishi, R; Tam, PHT; Tanaka, SJ; Tateishi, D; Temnikov, P; Terada, Y; Terauchi, K; Terzic, T; Teshima, M; Tluczykont, M; Tokanai, F; Torres, DF; Travnicek, P; Truzzi, S; Tutone, A; Uhlrich, G; Vacula, M; Acosta, MV; Verguilov, V; Viale, I; Vigliano, A; Vigorito, CF; Vitale, V; Voutsinas, G; Vovk, I; Vuillaume, T; Walter, R; Will, M; Yamamoto, T; Yamazaki, R; Yoshida, T; Yoshikoshi, T; Zywucka, N; Balbo, M; Eckert, D; Tramacere, A

ASTRONOMY & ASTROPHYSICS   673 巻   2023年5月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Astronomy and Astrophysics  

Context. Several new ultrahigh-energy (UHE) γ-ray sources have recently been discovered by the Large High Altitude Air Shower Observatory (LHAASO) collaboration. These represent a step forward in the search for the so-called Galactic PeVatrons, the enigmatic sources of the Galactic cosmic rays up to PeV energies. However, it has been shown that multi-TeV γ-ray emission does not necessarily prove the existence of a hadronic accelerator in the source; indeed this emission could also be explained as inverse Compton scattering from electrons in a radiation-dominated environment. A clear distinction between the two major emission mechanisms would only be made possible by taking into account multi-wavelength data and detailed morphology of the source. Aims. We aim to understand the nature of the unidentified source LHAASO J2108+5157, which is one of the few known UHE sources with no very high-energy (VHE) counterpart. Methods. We observed LHAASO J2108+5157 in the X-ray band with XMM-Newton in 2021 for a total of 3.8 hours and at TeV energies with the Large-Sized Telescope prototype (LST-1), yielding 49 hours of good-quality data. In addition, we analyzed 12 years of Fermi-LAT data, to better constrain emission of its high-energy (HE) counterpart 4FGL J2108.0+5155. We used naima and jetset software packages to examine the leptonic and hadronic scenario of the multi-wavelength emission of the source. Results. We found an excess (3.7σ) in the LST-1 data at energies E > 3 TeV. Further analysis of the whole LST-1 energy range, assuming a point-like source, resulted in a hint (2.2σ) of hard emission, which can be described with a single power law with a photon index of Σ = 1.6 ± 0.2 the range of 0.3 - 100 TeV. We did not find any significant extended emission that could be related to a supernova remnant (SNR) or pulsar wind nebula (PWN) in the XMM-Newton data, which puts strong constraints on possible synchrotron emission of relativistic electrons. We revealed a new potential hard source in Fermi-LAT data with a significance of 4σ and a photon index of Σ = 1.9 ± 0.2, which is not spatially correlated with LHAASO J2108+5157, but including it in the source model we were able to improve spectral representation of the HE counterpart 4FGL J2108.0+5155. Conclusions. The LST-1 and LHAASO observations can be explained as inverse Compton-dominated leptonic emission of relativistic electrons with a cutoff energy of 100-30+70 TeV. The low magnetic field in the source imposed by the X-ray upper limits on synchrotron emission is compatible with a hypothesis of a PWN or a TeV halo. Furthermore, the spectral properties of the HE counterpart are consistent with a Geminga-like pulsar, which would be able to power the VHE-UHE emission. Nevertheless, the lack of a pulsar in the neighborhood of the UHE source is a challenge to the PWN/TeV-halo scenario. The UHE γ rays can also be explained as π0 decay-dominated hadronic emission due to interaction of relativistic protons with one of the two known molecular clouds in the direction of the source. Indeed, the hard spectrum in the LST-1 band is compatible with protons escaping a shock around a middle-aged SNR because of their high low-energy cut-off, but the origin of the HE γ-ray emission remains an open question.

DOI： 10.1051/0004-6361/202245086

Web of Science

Scopus

MAGIC observations provide compelling evidence of hadronic multi-TeV emission from the putative PeVatron SNR G106.3+2.7

Abe H., Abe S., Acciari V.A., Agudo I., Aniello T., Ansoldi S., Antonelli L.A., Arbet Engels A., Arcaro C., Artero M., Asano K., Baack D., Babić A., Baquero A., Barres De Almeida U., Barrio J.A., Batković I., Baxter J., Becerra González J., Bednarek W., Bernardini E., Bernardos M., Berti A., Besenrieder J., Bhattacharyya W., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bošnjak , Burelli I., Busetto G., Carosi R., Carretero-Castrillo M., Castro-Tirado A.J., Ceribella G., Chai Y., Chilingarian A., Cikota S., Colombo E., Contreras J.L., Cortina J., Covino S., D'Amico G., D'Elia V., Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Delgado Mendez C., Depaoli D., Di Pierro F., Di Venere L., Do Souto Espiñeira E., Dominis Prester D., Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Escudero J., Fallah Ramazani V., Fariña L., Fattorini A., Font L., Fruck C., Fukami S., Fukazawa Y., García López R.J., Garczarczyk M., Gasparyan S., Gaug M., Giesbrecht Paiva J.G., Giglietto N., Giordano F., Gliwny P., Godinović N., Grau R., Green D., Green J.G., Hadasch D., Hahn A., Hassan T., Heckmann L., Herrera J., Hrupec D., Hütten M., Imazawa R., Inada T., Iotov R., Ishio K., Jiménez Martínez I., Jormanainen J., Kerszberg D., Kobayashi Y., Kubo H., Kushida J.

Astronomy and Astrophysics   671 巻   2023年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Astronomy and Astrophysics  

Context. Certain types of supernova remnants (SNRs) in our Galaxy are assumed to be PeVatrons, capable of accelerating cosmic rays (CRs) to ∼ PeV energies. However, conclusive observational evidence for this has not yet been found. The SNR G106.3+2.7, detected at 1- 100 TeV energies by different γ-ray facilities, is one of the most promising PeVatron candidates. This SNR has a cometary shape, which can be divided into a head and a tail region with different physical conditions. However, in which region the 100 TeV emission is produced has not yet been identified because of the limited position accuracy and/or angular resolution of existing observational data. Additionally, it remains unclear as to whether the origin of the γ-ray emission is leptonic or hadronic. Aims. With the better angular resolution provided by new MAGIC data compared to earlier γ-ray datasets, we aim to reveal the acceleration site of PeV particles and the emission mechanism by resolving the SNR G106.3+2.7 with 0.1 resolution at TeV energies. Methods. We observed the SNR G106.3+2.7 using the MAGIC telescopes for 121.7 h in total - after quality cuts - between May 2017 and August 2019. The analysis energy threshold is ∼0.2 TeV, and the angular resolution is 0.07-0.1. We examined the γ-ray spectra of different parts of the emission, whilst benefitting from the unprecedented statistics and angular resolution at these energies provided by our new data. We also used measurements at other wavelengths such as radio, X-rays, GeV γ-rays, and 10 TeV γ-rays to model the emission mechanism precisely. Results. We detect extended γ-ray emission spatially coincident with the radio continuum emission at the head and tail of SNR G106.3+2.7. The fact that we detect a significant γ-ray emission with energies above 6.0 TeV from only the tail region suggests that the emissions above 10 TeV detected with air shower experiments (Milagro, HAWC, Tibet ASγ and LHAASO) are emitted only from the SNR tail. Under this assumption, the multi-wavelength spectrum of the head region can be explained with either hadronic or leptonic models, while the leptonic model for the tail region is in contradiction with the emission above 10 TeV and X-rays. In contrast, the hadronic model could reproduce the observed spectrum at the tail by assuming a proton spectrum with a cutoff energy of ∼1 PeV for that region. Such high-energy emission in this middle-aged SNR (4-10 kyr) can be explained by considering a scenario where protons escaping from the SNR in the past interact with surrounding dense gases at present. Conclusions. The γ-ray emission region detected with the MAGIC telescopes in the SNR G106.3+2.7 is extended and spatially coincident with the radio continuum morphology. The multi-wavelength spectrum of the emission from the tail region suggests proton acceleration up to ∼PeV, while the emission mechanism of the head region could either be hadronic or leptonic.

DOI： 10.1051/0004-6361/202244931

Scopus

Gamma-ray observations of MAXI J1820+070 during the 2018 outburst

Abe H., Abe S., Acciari V. A., Aniello T., Ansoldi S., Antonelli L. A., Engels A. Arbet, Arcaro C., Artero M., Asano K., Baack D., Babic A., Baquero A., de Almeida U. Barres, Barrio J. A., Batkovic I, Baxter J., Gonzalez J. Becerra, Bednarek W., Bernardini E., Bernardos M., Berti A., Besenrieder J., Bhattacharyya W., Bigongiari C., Biland A., Blanch O., Bonnoli G., Bosnjak Z., Burelli I, Busetto G., Carosi R., Carretero-Castrillo M., Ceribella G., Chai Y., Chilingarian A., Cikota S., Colombo E., Contreras J. L., Cortina J., Covino S., D'Amico G., D'Elia V, Da Vela P., Dazzi F., De Angelis A., De Lotto B., Del Popolo A., Delfino M., Delgado J., Mendez C. Delgado, Depaoli D., Di Pierro F., Di Venere L., Prester D. Dominis, Donini A., Dorner D., Doro M., Elsaesser D., Emery G., Ramazani V. Fallah, Farina L., Fattorini A., Font L., Fruck C., Fukami S., Fukazawa Y., Lopez R. J. Garcia, Garczarczyk M., Gasparyan S., Gaug M., Paiva J. G. Giesbrecht, Giglietto N., Giordano F., Gliwny P., Godinovic N., Grau R., Green D., Green J. G., Hadasch D., Hahn A., Hassan T., Heckmann L., Herrera J., Hoang J., Hrupec D., Hutten M., Imazawa R., Inada T., Iotov R., Ishio K., Martinez I. Jimenez, Jormanainen J., Kerszberg D., Kobayashi Y., Kubo H., Kushida J., Lamastra A., Lelas D., Leone F., Lindfors E., Linhoff L., Lombardi S., Longo F., Lopez-Coto R., Lopez-Moya M., Lopez-Oramas A., Loporchio S., Lorini A., Lyard E., Fraga B. Machado de Oliveira, Majumdar P., Makariev M., Maneva G., Mang N., Manganaro M., Mangano S., Mannheim K., Mariotti M., Martinez M., Aguilar A. Mas, Mazin D., Menchiari S., Mender S., Micanovic S., Miceli D., Miener T., Miranda J. M., Mirzoyan R., Molina E., Mondal H. A., Moralejo A., Morcuende D., Moreno V, Nakamori T., Nanci C., Nava L., Neustroev V, Rosillo M. Nievas, Nigro C., Nilsson K., Nishijima K., Ekoume T. Njoh, Noda K., Nozaki S., Ohtani Y., Oka T., Okumura A., Otero-Santos J., Paiano S., Palatiello M., Paneque D., Paoletti R., Paredes J. M., Pavletic L., Persic M., Pihet M., Pirola G., Podobnik F., Moroni P. G. Prada, Prandini E., Principe G., Priyadarshi C., Puljak I, Rhode W., Ribo M., Rico J., Righi C., Rugliancich A., Sahakyan N., Saito T., Sakurai S., Satalecka K., Saturni F. G., Schleicher B., Schmidt K., Schmuckermaier F., Schubert J. L., Schweizer T., Sitarek J., Sliusar V, Sobczynska D., Spolon A., Stamerra A., Striskovic J., Strom D., Strzys M., Suda Y., Suric T., Tajima H., Takahashi M., Takeishi R., Tavecchio F., Temnikov P., Terauchi K., Terzic T., Teshima M., Tosti L., Truzzi S., Tutone A., Ubach S., van Scherpenberg J., Acosta M. Vazquez, Ventura S., Verguilov V., Viale I, Vigorito C. F., Vitale V., Vovk I, Walter R., Will M., Wunderlich C., Yamamoto T., Zaric D., Abdalla H., Aharonian F., Benkhali F. Ait, Anguner E. O., Ashkar H., Backes M., Baghmanyan V, Martins V. Barbosa, Batzofin R., Becherini Y., Berge D., Bernloehr K., Bottcher M., Boisson C., Bolmont J., de Lavergne M. de Bony, Bradascio F., Breuhaus M., Brose R., Brun F., Bulik T., Bylund T., Cangemi F., Caroff S., Casanova S., Cerruti M., Chand T., Chandra S., Chen A., Chibueze O. U., Cotter G., Cristofari P., Mbarubucyeye J. Damascene, Devin J., Djannati-Atai A., Dmytriiev A., Egberts K., Ernenwein J-P, Fiasson A., de Clairfontaine G. Fichet, Fontaine G., Fuessling M., Funk S., Gabici S., Ghafourizadeh S., Giavitto G., Glawion D., Glicenstein J. F., Goswami P., Grolleron G., Hinton J. A., Horbe M., Hoischen C., Holch T. L., Holler M., Horns D., Huang Zhiqiu, Jamrozy M., Jankowsky F., Joshi V, Jung-Richardt I, Kasai E., Katarzynski K., Katz U., Khelifi B., Kluzniak W., Komin Nu, Kosack K., Kostunin D., Lang R. G., Le Stum S., Lemiere A., Lemoine-Goumard M., Lenain J-P, Leuschner F., Lohse T., Luashvili A., Lypova I, Mackey J., Majumdar J., Malyshev D., Malyshev D., Marandon V, Marchegiani P., Marti-Devesa G., Marx R., Maurin G., Meyer M., Mitchell A., Moderski R., Mohrmann L., Montanari A., Moulin E., Muller J., Murach T., Nakashima K., de Naurois M., Nayerhoda A., Niemiec J., Noel A. Pniyana, O'Brien P., Ohm S., Olivera-Nieto L., Wilhelmi E. de Ona, Ostrowski M., Panny S., Panter M., Parsons R. D., Poireau V, Prokhorov D. A., Prokoph H., Puehlhofer G., Punch M., Quirrenbach A., Reichherzer P., Reimer A., Reimer O., Renaud M., Rieger F., Rowell G., Rudak B., Ricarte H. Rueda, Ruiz-Velasco E., Sahakian V, Salzmann H., Santangelo A., Sasaki M., Schaefer J., Schussler F., Schutte H. M., Schwanke U., Shapopi J. N. S., Sol H., Specovius A., Spencer S., Stawarz L., Steenkamp R., Steinmassl S., Steppa C., Sushch I, Suzuki H., Takahashi T., Tanaka T., Thorpe-Morgan C., Tluczykont M., Tomankova L., Tsuji N., Uchiyama Y., van Eldik C., van Soelen B., Vecchi M., Veh J., Venter C., Vink J., Wagner S. J., White R., Wierzcholska A., Wong Yu Wun, Yusafzai A., Zacharias M., Zanin R., Zargaryan D., Zdziarski A. A., Zech A., Zhu S. J., Zouari S., Zywucka N., Acharyya A., Adams C. B., Batista P., Benbow W., Capasso M., Christiansen J. L., Chromey A. J., Errando M., Falcone A., Feng Q., Finley J. P., Foote G. M., Fortson L., Furniss A., Gent A., Hanlon W. E., Hervet O., Holder J., Hona B., Humensky T. B., Jin W., Kaaret P., Kertzman M., Kherlakian M., Kleiner T. K., Kumar S., Lang M. J., Lundy M., Maier G., McGrath C. E., Millis J., Moriarty P., Mukherjee R., O'Brien S., Ong R. A., Park N., Patel S. R., Pfrang K., Pohl M., Pueschel E., Quinn J., Ragan K., Reynolds P. T., Ribeiro D., Roache E., Ryan J. L., Sadeh I, Saha L., Santander M., Sembroski G. H., Shang R., Splettstoesser M., Tak D., Tucci J. V, Weinstein A., Williams D. A., Williamson T. J., Bosch-Ramon V, Celma C., Linares M., Russell D. M., Sala G.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY   517 巻 ( 4 ) 頁： 4736 - 4751   2022年12月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Monthly Notices of the Royal Astronomical Society  

MAXI J1820+070 is a low-mass X-ray binary with a black hole (BH) as a compact object. This binary underwent an exceptionally bright X-ray outburst from 2018 March to October, showing evidence of a non-thermal particle population through its radio emission during this whole period. The combined results of 59.5 h of observations of the MAXI J1820+070 outburst with the H.E.S.S., MAGIC and VERITAS experiments at energies above 200 GeV are presented, together with Fermi-LAT data between 0.1 and 500 GeV, and multiwavelength observations from radio to X-rays. Gamma-ray emission is not detected from MAXI J1820+070, but the obtained upper limits and the multiwavelength data allow us to put meaningful constraints on the source properties under reasonable assumptions regarding the non-thermal particle population and the jet synchrotron spectrum. In particular, it is possible to show that, if a high-energy (HE) gamma-ray emitting region is present during the hard state of the source, its predicted flux should be at most a factor of 20 below the obtained Fermi-LAT upper limits, and closer to them for magnetic fields significantly below equipartition. During the state transitions, under the plausible assumption that electrons are accelerated up to ∼500 GeV, the multiwavelength data and the gamma-ray upper limits lead consistently to the conclusion that a potential HE and very-HE gamma-ray emitting region should be located at a distance from the BH ranging between 1011 and 1013 cm. Similar outbursts from low-mass X-ray binaries might be detectable in the near future with upcoming instruments such as CTA.

DOI： 10.1093/mnras/stac2686

Web of Science

Scopus

Active Galactic Nuclei population studies with the Cherenkov Telescope Array

Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W., Berge D., Bernardini E., Bernardos M.I., Bernlöhr K., Berti A.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Cherenkov Telescope Array (CTA) observatory is the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Building on the strengths of current IACTs, CTA is designed to achieve an order of magnitude improvement in sensitivity, with unprecedented angular and energy resolution. CTA will also increase the energy reach of IACTs, observing photons in the energy range from 20 GeV to beyond 100 TeV. These advances in performance will see CTA heralding in a new era for high-energy astrophysics, with the emphasis shifting from source discovery, to population studies and precision measurements. In this talk we discuss CTA’s ability to conduct source population studies of γ-ray bright active galactic nuclei and how this ability will enhance our understanding on the redshift evolution of this dominant γ-ray source class.

Scopus

Reconstruction of stereoscopic CTA events using deep learning with CTLearn

Miener T., Nieto D., Brill A., Spencer S., Contreras J.L., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Cherenkov Telescope Array (CTA), conceived as an array of tens of imaging atmospheric Cherenkov telescopes (IACTs), is an international project for a next-generation ground-based gamma-ray observatory, aiming to improve on the sensitivity of current-generation instruments a factor of five to ten and provide energy coverage from 20 GeV to more than 300 TeV. Arrays of IACTs probe the very-high-energy gamma-ray sky. Their working principle consists of the simultaneous observation of air showers initiated by the interaction of very-high-energy gamma rays and cosmic rays with the atmosphere. Cherenkov photons induced by a given shower are focused onto the camera plane of the telescopes in the array, producing a multi-stereoscopic record of the event. This image contains the longitudinal development of the air shower, together with its spatial, temporal, and calorimetric information. The properties of the originating very-high-energy particle (type, energy, and incoming direction) can be inferred from those images by reconstructing the full event using machine learning techniques. In this contribution, we present a purely deep-learning driven, full-event reconstruction of simulated, stereoscopic IACT events using CTLearn. CTLearn is a package that includes modules for loading and manipulating IACT data and for running deep learning models, using pixel-wise camera data as input.

Scopus

Reconstruction of extensive air shower images of the first Large Size Telescope prototype of CTA using a novel likelihood technique

Emery G., Alispach C., Dalchenko M., Foffano L., Heller M., Montaruli T., Abe H., Aguasca A., Agudo I., Antonelli L.A., Aramo C., Armstrong T., Artero M., Asano K., Ashkar H., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardos M.I., Berti A., Biederbeck N., Bigongiari C., Blanch O., Bonnoli G., Bordas P., Bose D., Bulgarelli A., Burelli I., Buscemi M., Cardillo M., Caroff S., Carosi A., Cassol F., Cerruti M., Chai Y., Cheng K., Chikawa M., Chytka L., Contreras J.L., Cortina J., Costantini H., De Angelis A., de Bony de Lavergne M., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Depaoli D., Di Pierro F., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Elsässer D., Escudero J., Fiasson A., Fonseca M.V., Freixas Coromina L., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Giglietto N., Giordano F., Gliwny P., Godinovic N., Green D., Grespan P., Gunji S., Hackfeld J., Hadasch D., Hahn A., Hassan T., Hayashi K., Heckmann L., Herrera Llorente J., Hirotani K., Hoffmann D., Horns D., Houles J., Hrabovsky M., Hrupec D., Hui D., Hütten M., Inada T., Inome Y., Iori M., Ishio K., Iwamura Y., Jacquemont M., Jimenez Martinez I.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

Ground-based gamma-ray astronomy aims at reconstructing the energy and direction of gamma rays from the extensive air showers they initiate in the atmosphere. Imaging Atmospheric Cherenkov Telescopes (IACT) collect the Cherenkov light induced by secondary charged particles in extensive air showers (EAS), creating an image of the shower in a camera positioned in the focal plane of optical systems. This image is used to evaluate the type, energy and arrival direction of the primary particle that initiated the shower. This contribution shows the results of a novel reconstruction method based on likelihood maximization. The novelty with respect to previous likelihood reconstruction methods lies in the definition of a likelihood per single camera pixel, accounting not only for the total measured charge, but also for its development over time. This leads to more precise reconstruction of shower images. The method is applied to observations of the Crab Nebula acquired with the Large Size Telescope prototype (LST-1) deployed at the northern site of the Cherenkov Telescope Array.

Scopus

Prototype Schwarzschild-Couder Telescope for the Cherenkov Telescope Array: Commissioning the Optical System

Ribeiro D., 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., 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.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

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 multiwavelength 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 (0.78m diameter) implementation of the high-resolution camera (6mm/0.067deg 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 commissioning activities aim to meet the on-axis PSF design goal of 2.6 arcmin, verify the off-axis performance of the pSCT OS, and develop techniques to maintain alignment stability over telescope structural deformations from pointing and temperature variations. In this contribution, we report on the commissioning status, the optical alignment procedures adopted for segmented OS, and alignment progress to verify and validate design requirements.

Scopus

Prototype Open Event Reconstruction Pipeline for the Cherenkov Telescope Array

Nöthe M., Kosack K., Nickel L., Peresano M., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W., Berge D.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray observatory currently under construction. It will improve over the current generation of imaging atmospheric Cherenkov telescopes (IACTs) by a factor of five to ten in sensitivity and it will be able to observe the whole sky from a combination of two sites: a northern site in La Palma, Spain, and a southern one in Paranal, Chile. CTA will also be the first open gamma-ray observatory. Accordingly, the data analysis pipeline is developed as open-source software. The event reconstruction pipeline accepts raw data of the telescopes and processes it to produce suitable input for the higher-level science tools. Its primary tasks include reconstructing the physical properties of each recorded shower and providing the corresponding instrument response functions. ctapipe is a framework providing algorithms and tools to facilitate raw data calibration, image extraction, image parameterization and event reconstruction. Its main focus is currently the analysis of simulated data but it has also been successfully applied for the analysis of data obtained with the first CTA prototype telescopes, such as the Large-Sized Telescope 1 (LST-1). pyirf is a library to calculate IACT instrument response functions, needed to obtain physics results like spectra and light curves, from the reconstructed event lists. Building on these two, protopipe is a prototype for the event reconstruction pipeline for CTA. Recent developments in these software packages will be presented.

Scopus

Prospects for Galactic transient sources detection with the Cherenkov Telescope Array

López-Oramas A., Bulgarelli A., Chaty S., Chernyakova M., Gnatyk R., Hnatyk B., Kantzas D., Markoff S., McKeague S., Mereghetti S., Mestre E., di Piano A., Romano P., Sadeh I., Sergijenko O., Sidoli L., Spolon A., de Ona Wilhelmi E., Piano G., Zampieri L., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

Several types of Galactic sources, like magnetars, microquasars, novae or pulsar wind nebulae flares, display transient emission in the X-ray band. Some of these sources have also shown emission at MeV-GeV energies. However, none of these Galactic transients have ever been detected in the very-high-energy (VHE; E>100 GeV) regime by any Imaging Air Cherenkov Telescope (IACT). The Galactic Transient task force is a part of the Transient Working group of the Cherenkov Telescope Array (CTA) Consortium. The task force investigates the prospects of detecting the VHE counterpart of such sources, as well as their study following Target of Opportunity (ToO) observations. In this contribution, we will show some of the results of exploring the capabilities of CTA to detect and observe Galactic transients; we assume different array configurations and observing strategies.

Scopus

Physics Performance of the Large-Sized Telescope prototype of the Cherenkov Telescope Array

Abe H., Aguasca A., Agudo I., Antonelli L.A., Aramo C., Armstrong T., Artero M., Asano K., Ashkar H., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardos M.I., Berti A., Biederbeck N., Bigongiari C., Blanch O., Bonnoli G., Bordas P., Bose D., Bulgarelli A., Burelli I., Buscemi M., Cardillo M., Caroff S., Carosi A., Cassol F., Cerruti M., Chai Y., Cheng K., Chikawa M., Chytka L., Contreras J.L., Cortina J., Costantini H., Dalchenko M., De Angelis A., de Bony de Lavergne M., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Depaoli D., Di Pierro F., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Elsässer D., Emery G., Escudero J., Fiasson A., Foffano L., Fonseca M.V., Freixas Coromina L., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Giglietto N., Giordano F., Gliwny P., Godinovic N., Green D., Grespan P., Gunji S., Hackfeld J., Hadasch D., Hahn A., Hassan T., Hayashi K., Heckmann L., Heller M., Herrera Llorente J., Hirotani K., Hoffmann D., Horns D., Houles J., Hrabovsky M., Hrupec D., Hui D., Hütten M., Inada T., Inome Y., Iori M., Ishio K., Iwamura Y., Jacquemont M., Jimenez Martinez I., Jouvin L., Jurysek J.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Large-Sized Telescope (LST) prototype of the future Cherenkov Telescope Array (CTA) is located at the Northern site of CTA, on the Canary Island of La Palma. It is designed to provide optimal performance in the lowest part of the energy range covered by CTA, observing gamma rays down to energies of tens of GeV. The LST prototype started performing astronomical observations in November 2019 during the commissioning of the telescope and it has been taking data since then. In this contribution, we will present the tuning of the characteristics of the telescope in the Monte Carlo (MC) simulations to describe the data obtained, the estimation of its angular and energy resolution, and an evaluation of its sensitivity, both with simulations and with observations of the Crab Nebula.

Scopus

Performance of the Cherenkov Telescope Array in the presence of clouds

Pecimotika M., Adamczyk K., Prester D.D., Gueta O., Hrupec D., Maier G., Mićanović S., Pavletić L., Sitarek J., Sobczyńska D., Szanecki M., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

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.

Scopus

Performance of a proposed event-type based analysis for the Cherenkov Telescope Array

Hassan T., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W., Berge D., Bernardini E., Bernardos M.I., Bernlöhr K.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Cherenkov Telescope Array (CTA) will be the next-generation observatory in the field of very-high-energy (20 GeV to 300 TeV) gamma-ray astroparticle physics. Classically, data analysis in the field maximizes sensitivity by applying quality cuts on the data acquired. These cuts, optimized using Monte Carlo simulations, select higher quality events from the initial dataset. Subsequent steps of the analysis typically use the surviving events to calculate one set of instrument response functions (IRFs). An alternative approach is the use of event types, as implemented in experiments such as the Fermi-LAT. In this approach, events are divided into sub-samples based on their reconstruction quality, and a set of IRFs is calculated for each sub-sample. The sub-samples are then combined in a joint analysis, treating them as independent observations. This leads to an improvement in performance parameters such as sensitivity, angular and energy resolution. Data loss is reduced since lower quality events are included in the analysis as well, rather than discarded. In this study, machine learning methods will be used to classify events according to their expected angular reconstruction quality. We will report the impact on CTA high-level performance when applying such an event-type classification, compared to the classical procedure.

Scopus

Monte Carlo Simulations and Validation of NectarCAM, a Medium Sized Telescope Camera for CTA

Armstrong T.P., Costantini H., Glicenstein J.F., Lenain J.P., Schwanke U., Tavernier T., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The upcoming Cherenkov Telescope Array (CTA) ground-based gamma-ray observatory will open up our view of the very high energy Universe, offering an improvement in sensitivity of 5-10 times that of previous experiments. NectarCAM is one of the proposed cameras for the Medium-Sized Telescopes (MST) which have been designed to cover the core energy range of CTA, from 100 GeV to 10 TeV. The final camera will be capable of GHz sampling and provide a field of view of 8 degrees with its 265 modules of 7 photomultiplier each (for a total of 1855 pixels). In order to validate the performance of NectarCAM, a partially-equipped prototype has been constructed consisting of only the inner 61-modules. It has so far undergone testing at the integration test-bench facility in CEA Paris-Saclay (France) and on a prototype of the MST structure in Adlershof (Germany). To characterize the performance of the prototype, Monte Carlo simulations were conducted using a detailed model of the 61 module camera in the CORSIKA/sim_telarray framework. This contribution provides an overview of this work including the comparison of trigger and readout performance on test-bench data and trigger and image parameterization performance during on-sky measurements.

Scopus

Monitoring the pointing of the prototype LST-1 using star reconstruction in the Cherenkov camera

Foffano L., Carosi A., Dalchenko M., Heller M., Della Volpe D., Montaruli T., Abe H., Aguasca A., Agudo I., Antonelli L.A., Aramo C., Armstrong T., Artero M., Asano K., Ashkar H., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardos M.I., Berti A., Biederbeck N., Bigongiari C., Blanch O., Bonnoli G., Bordas P., Bose D., Bulgarelli A., Burelli I., Buscemi M., Cardillo M., Caroff S., Cassol F., Cerruti M., Chai Y., Cheng K., Chikawa M., Chytka L., Contreras J.L., Cortina J., Costantini H., De Angelis A., de Bony de Lavergne M., Deleglise G., Delgado C., Delgado Mengual J., Depaoli D., Di Pierro F., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Elsässer D., Emery G., Escudero J., Fiasson A., Fonseca M.V., Freixas Coromina L., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Giglietto N., Giordano F., Gliwny P., Godinovic N., Green D., Grespan P., Gunji S., Hackfeld J., Hadasch D., Hahn A., Hassan T., Hayashi K., Heckmann L., Herrera Llorente J., Hirotani K., Hoffmann D., Horns D., Houles J., Hrabovsky M., Hrupec D., Hui D., Hütten M., Inada T., Inome Y., Iori M., Ishio K., Iwamura Y., Jacquemont M., Jimenez Martinez I., Jouvin L.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The first Large-Sized Telescope (LST-1) proposed for the forthcoming Cherenkov Telescope Array (CTA) has started to operate in 2019 in La Palma. The large structure of LST-1 - with a 23 m mirror dish diameter - imposes a strict control of its deformations that could affect the pointing accuracy and its overall performance. According to CTA specifications that are conceived to resolve e.g. the fine structure of galactic sources, the LST post-calibration pointing accuracy should be better than 14 arcseconds. To fulfill this requirement, the telescope pointing precision is monitored with two dedicated CCD cameras located at the dish center. The analysis of their images allows us to disentangle different systematic deformations of the structure. In this work, we investigate a complementary approach that offers the possibility to monitor the pointing of the telescope during the acquisition of sky data. After properly cleaning the events from the Cherenkov showers, the reconstructed positions of the stars imaged in the camera field of view are compared to their nominal expected positions in catalogues. This provides a direct measurement of the telescope pointing, that can be used to cross-check the other methods and as a real-time monitoring of the optical properties of the telescope and of the pointing corrections applied by the bending models. Additionally, this method benefits from not relying on specific hardware or dedicated observations. In this contribution we will illustrate this analysis and show results based on simulations of LST-1.

Scopus

HAWC J2227+610: a potential PeVatron candidate for the CTA in the northern hemisphere

Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W., Berge D., Bernardini E., Bernardos M.I., Bernlöhr K., Berti A.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

Recent observations of the gamma-ray source HAWC J2227+610 by Tibet AS+MD and LHAASO confirm the special interest of this source as a galactic PeVatron candidate in the northern hemisphere. HAWC J2227+610 emits Very High Energy (VHE) gamma-rays up to 500 TeV, from a region coincident with molecular clouds and significantly displaced from the nearby pulsar J2229+6114. Even if this morphology favours an hadronic origin, both leptonic or hadronic models can describe the current VHE gamma-ray emission. The morphology of the source is not well constrained by the present measurements and a better characterisation would greatly help the understanding of the underlying particle acceleration mechanisms. The Cherenkov Telescope Array (CTA) will be the future most sensitive Imaging Atmospheric Cherenkov Telescope and, thanks to its unprecedented angular resolution, could contribute to better constrain the nature of this source. The present work investigates the potentiality of CTA to study the morphology and the spectrum of HAWC J2227+610. For this aim, the source is simulated assuming the hadronic model proposed by the Tibet AS+MD collaboration, recently fitted on multi-wavelength data, and two spatial templates associated to the source nearby molecular clouds. Different CTA layouts and observation times are considered. A 3D map based analysis shows that CTA is able to significantly detect the extension of the source and to attribute higher detection significance to the simulated molecular cloud template compared to the alternative one. CTA data does not allow to disentangle the hadronic and the leptonic emission models. However, it permits to correctly reproduce the simulated parent proton spectrum characterized by a ∼ 500 TeV cutoff.

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First follow-up of transient events with the CTA Large Size Telescope prototype

Kobayshi Y., Sanchez D., Abe H., Aguasca A., Agudo I., Antonelli L.A., Aramo C., Armstrong T., Artero M., Asano K., Ashkar H., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardos M.I., Berti A., Biederbeck N., Bigongiari C., Blanch O., Bonnoli G., Bordas P., Bose D., Bulgarelli A., Burelli I., Buscemi M., Cardillo M., Caroff S., Carosi A., Cassol F., Cerruti M., Chai Y., Cheng K., Chikawa M., Chytka L., Contreras J.L., Cortina J., Costantini H., Dalchenko M., De Angelis A., de Bony de Lavergne M., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Depaoli D., Di Pierro F., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Elsässer D., Emery G., Escudero J., Fiasson A., Foffano L., Fonseca M.V., Freixas Coromina L., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Giglietto N., Giordano F., Gliwny P., Godinovic N., Green D., Grespan P., Gunji S., Hackfeld J., Hadasch D., Hahn A., Hassan T., Hayashi K., Heckmann L., Heller M., Herrera Llorente J., Hirotani K., Hoffmann D., Horns D., Houles J., Hrabovsky M., Hrupec D., Hui D., Hütten M., Inada T., Inome Y., Iori M., Ishio K., Iwamura Y., Jacquemont M., Jimenez Martinez I.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The recent detection of a very high energy (VHE) emission from Gamma-Ray Bursts (GRBs) above 100 GeV performed by the MAGIC and H.E.S.S. collaborations, has represented a significant, long-awaited result for the VHE astrophysics community. Although these results' scientific impact has not yet been fully exploited, the possibility to detect VHE gamma-ray signals from GRBs has always been considered crucial for clarifying the poorly known physics of these objects. Furthermore, the discovery of high-energy neutrinos and gravitational waves associated with astrophysical sources have definitively opened the era of multi-messenger astrophysics, providing unique insights into the physics of extreme cosmic accelerators. In the near future, the Cherenkov Telescope Array (CTA) will play a major role in these observations. Within this framework, the Large Size Telescopes (LSTs) will be the instruments best suited to significantly impact on short time-scale transients follow-up thanks to their fast slewing and large effective area. The observations of the early emission phase of a wide range of transient events with good sensitivity below 100 GeV will allow us to open new opportunities for time-domain astrophysics in an energy range not affected by selective absorption processes typical of other wavelengths. In this contribution, we will report about the observational program and first transients follow-up observations performed by the LST-1 telescope currently in its commissioning phase on La Palma, Canary Islands, the CTA northern hemisphere site.

Scopus

Exploring the population of Galactic very-high-energy γ-ray sources

Steppa C., Egberts K., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Baroncelli L., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W., Belfiore A., Bellizzi L., Belmont R., Benbow W., Berge D., Bernardini E., Bernardos M.I.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

At very high energies (VHE), the emission of γ rays is dominated by discrete sources. Due to the limited resolution and sensitivity of current-generation instruments, only a small fraction of the total Galactic population of VHE γ-ray sources has been detected significantly. The larger part of the population can be expected to contribute as a diffuse signal alongside emission originating from propagating cosmic rays. Without quantifying the source population, it is not possible to disentangle these two components. Based on the H.E.S.S. Galactic plane survey, a numerical approach has been taken to develop a model of the population of Galactic VHE γ-ray sources, which is shown to account accurately for the observational bias. We present estimates of the absolute number of sources in the Galactic Plane and their contribution to the total VHE γ-ray emission for five different spatial source distributions. Prospects for CTA and its ability to constrain the model are discussed. Finally, first results of an extension of our modelling approach using machine learning to extract more information from the available data set are presented.

Scopus

Development of an advanced SiPM camera for the Large Size Telescope of the Cherenkov Telescope Array Observatory

Bellato M., Bergnoli A., Bernasconi E., Biland A., Charbon E., Corti D., Gascón D., Gómez S., Ziȩtara K., Abe H., Aguasca A., Agudo I., Antonelli L.A., Aramo C., Armstrong T., Artero M., Asano K., Ashkar H., Aubert P., Baktash A., Bamba A., Baquero Larriva A., Baroncelli L., Barres de Almeida U., Barrio J.A., Batkovic I., Becerra González J., Bernardos M.I., Berti A., Biederbeck N., Bigongiari C., Blanch O., Bonnoli G., Bordas P., Bose D., Bulgarelli A., Burelli I., Buscemi M., Cardillo M., Caroff S., Carosi A., Cassol F., Cerruti M., Chai Y., Cheng K., Chikawa M., Chytka L., Contreras J.L., Cortina J., Costantini H., Dalchenko M., De Angelis A., de Bony de Lavergne M., Deleglise G., Delgado C., Delgado Mengual J., della Volpe D., Depaoli D., Di Pierro F., Di Venere L., Díaz C., Dominik R.M., Dominis Prester D., Donini A., Dorner D., Doro M., Elsässer D., Emery G., Escudero J., Fiasson A., Foffano L., Fonseca M.V., Freixas Coromina L., Fukami S., Fukazawa Y., Garcia E., Garcia López R., Giglietto N., Giordano F., Gliwny P., Godinovic N., Green D., Grespan P., Gunji S., Hackfeld J., Hadasch D., Hahn A., Hassan T., Hayashi K., Heckmann L., Heller M., Herrera Llorente J., Hirotani K., Hoffmann D., Horns D., Houles J., Hrabovsky M., Hrupec D., Hui D., Hütten M.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

Silicon photomultipliers (SiPMs) have become the baseline choice for cameras of the small-sized telescopes (SSTs) of the Cherenkov Telescope Array (CTA). On the other hand, SiPMs are relatively new to the field and covering large surfaces and operating at high data rates still are challenges to outperform photomultipliers (PMTs). The higher sensitivity in the near infra-red and longer signals compared to PMTs result in higher night sky background rate for SiPMs. However, the robustness of the SiPMs represents a unique opportunity to ensure long-term operation with low maintenance and better duty cycle than PMTs. The proposed camera for large size telescopes will feature 0.05◦ pixels, low power and fast front-end electronics and a fully digital readout. In this work, we present the status of dedicated simulations and data analysis for the performance estimation. The design features and the different strategies identified, so far, to tackle the demanding requirements and the improved performance are described.

Scopus

Detection of the Crab Nebula by the prototype Schwarzschild-Couder Telescope

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., Brown A.M., 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., Holder J., 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., 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., Tajima H., Taylor L.P., Tosti L., Tovmassian G., Tripodo G., Vagelli V., Valentino M., Vandenbroucke J., Vassiliev V.V., Williams D.A., Zink A.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Schwarzschild-Couder Telescope (SCT) is a medium-sized telescope technology proposed for the Cherenkov Telescope Array. It uses a novel dual-mirror optical design that removes comatic aberrations across its entire field of view. The SCT camera employs high-resolution silicon photomultiplier (SiPM) sensors with a pixel size of 4 arcminutes. A prototype SCT (pSCT) has been constructed at the Fred Lawrence Whipple Observatory in Arizona, USA. An observing campaign in 2020, with a partial camera of 1600 pixels (2.7 degrees by 2.7 degrees field of view) resulted in detection of the Crab Nebula at 8.6 sigma statistical significance. Work on the pSCT camera and optical system is ongoing to improve performance and prepare for an upcoming camera upgrade. The pSCT camera upgrade will replace the current camera modules with improved SiPMs and readout electronics and will expand the camera to its full design field of view of 8 degrees in diameter (11,328 pixels). The fully upgraded pSCT will enable next-generation very-high-energy gamma-ray astrophysics through excellent background rejection and angular resolution. In this presentation we describe first results from the successful operation of the pSCT and future plans.

Scopus

Detection methods for the Cherenkov Telescope Array at very-short exposure times

Di Piano A., Bulgarelli A., Fioretti V., Baroncelli L., Parmiggiani N., Longo F., Stamerra A., López-Oramas A., Stratta G., De Cesare G., Abdalla H., Abe H., Abe S., Abusleme A., Acero F., Acharyya A., Acín Portella V., Ackley K., Adam R., Adams C., Adhikari S.S., Aguado-Ruesga I., Agudo I., Aguilera R., Aguirre-Santaella A., Aharonian F., Alberdi A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Alves Batista R., Amans J.P., Amati L., Amato E., Ambrogi L., Ambrosi G., Ambrosio M., Ammendola R., Anderson J., Anduze M., Angüner E.O., Antonelli L.A., Antonuccio V., Antoranz P., Anutarawiramkul R., Aragunde Gutierrez J., Aramo C., Araudo A., Araya M., Arbet-Engels A., Arcaro C., Arendt V., Armand C., Armstrong T., Arqueros F., Arrabito L., Arsioli B., Artero M., Asano K., Ascasíbar Y., Aschersleben J., Ashley M., Attinà P., Aubert P., Singh C.B., Baack D., Babic A., Backes M., Baena V., Bajtlik S., Baktash A., Balazs C., Balbo M., Ballester O., Ballet J., Balmaverde B., Bamba A., Bandiera R., Baquero Larriva A., Barai P., Barbier C., Barbosa Martins V., Barcelo M., Barkov M., Barnard M., Barres de Almeida U., Barrio J.A., Bastieri D., Batista P.I., Batkovic I., Bauer C., Bautista-González R., Baxter J., Becciani U., Becerra González J., Becherini Y., Beck G., Becker Tjus J., Bednarek W.

Proceedings of Science   395 巻   2022年3月

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記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Proceedings of Science  

The Cherenkov Telescope Array (CTA) will be the next generation ground-based observatory for very-high-energy (VHE) gamma-ray astronomy, with the deployment of tens of highly sensitive and fast-reacting Cherenkov telescopes. It will cover a wide energy range (20 GeV - 300 TeV) with unprecedented sensitivity. To maximize the scientific return, the observatory will be provided with an online software system that will perform the first analysis of scientific data in real-time. This study investigates the precision and accuracy of available science tools and analysis techniques for the short-term detection of gamma-ray sources, in terms of sky localization, detection significance and, if significant detection is achieved, a first estimation of the integral photon flux. The scope is to evaluate the feasibility of the algorithms' implementation in the real-time analysis of CTA. In this contribution we present a general overview of the methods and some of the results for the test case of the short-term detection of a gamma-ray burst afterglow, as the VHE counterpart of a gravitational wave event.

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