MAGIC observations provide compelling evidence of the 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, Ž.; 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.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Linhoff, L.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Lorini, A.; Lyard, E.; Machado de Oliveira Fraga, B.; Majumdar, P.; Makariev, M.; Maneva, G.; Mang, N.; Manganaro, M.; Mangano, S.; Mannheim, K.; Mariotti, M.; Martínez, M.; Mas Aguilar, A.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, 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.; Nievas Rosillo, M.; Nigro, C.; Nilsson, K.; Nishijima, K.; Njoh Ekoume, T.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Okumura, A.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Persic, M.; Pihet, M.; Pirola, G.; Podobnik, F.; Prada Moroni, P. G.; Prandini, E.; Principe, G.; Priyadarshi, C.; Rhode, W.; Ribó, 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.; Strišković, J.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Tajima, H.; Takahashi, M.; Takeishi, R.; Tavecchio, F.; Temnikov, P.; Terauchi, K.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Viale, I.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Walter, R.; Will, M.; Wunderlich, C.; Yamamoto, T.; Zarić, D.

doi:10.48550/arXiv.2211.15321

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, it is not identified in which region the 100 TeV emission is produced due to the limited position accuracy and/or angular resolution of existing observational data. Additionally, it remains unclear whether the origin of the γ-ray emission is leptonic or hadronic. Aims. With the better angular resolution provided by these 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 hours 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◦ . The γ-ray spectra of different parts of the emission are examined, benefiting from the unprecedented statistics and angular resolution at these energies provided by our new data. The measurements at other wavelengths such as radio, X-rays, GeV γ-rays and 10 TeV γ-rays are also used to model the emission mechanism precisely. Results. We detected 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 detected a significant γ-ray emission with energies above 6.0 TeV from the tail region only 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 the tail region. Such a high energy emission in this middle-aged SNR (4–10 kyr) can be explained by considering the scenario that 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 can be both hadronic or leptonic.

MAGIC observations provide compelling evidence of the 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, Ž.; 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.; Lamastra, A.; Lelas, D.; Leone, F.; Lindfors, E.; Linhoff, L.; Lombardi, S.; Longo, F.; López-Coto, R.; López-Moya, M.; López-Oramas, A.; Loporchio, S.; Lorini, A.; Lyard, E.; Machado de Oliveira Fraga, B.; Majumdar, P.; Makariev, M.; Maneva, G.; Mang, N.; Manganaro, M.; Mangano, S.; Mannheim, K.; Mariotti, M.; Martínez, M.; Mas Aguilar, A.; Mazin, D.; Menchiari, S.; Mender, S.; Mićanović, 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.; Nievas Rosillo, M.; Nigro, C.; Nilsson, K.; Nishijima, K.; Njoh Ekoume, T.; Noda, K.; Nozaki, S.; Ohtani, Y.; Oka, T.; Okumura, A.; Otero-Santos, J.; Paiano, S.; Palatiello, M.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Pavletić, L.; Persic, M.; Pihet, M.; Pirola, G.; Podobnik, F.; Prada Moroni, P. G.; Prandini, E.; Principe, G.; Priyadarshi, C.; Rhode, W.; Ribó, 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.; Strišković, J.; Strom, D.; Strzys, M.; Suda, Y.; Surić, T.; Tajima, H.; Takahashi, M.; Takeishi, R.; Tavecchio, F.; Temnikov, P.; Terauchi, K.; Terzić, T.; Teshima, M.; Tosti, L.; Truzzi, S.; Tutone, A.; Ubach, S.; van Scherpenberg, J.; Vazquez Acosta, M.; Ventura, S.; Verguilov, V.; Viale, I.; Vigorito, C. F.; Vitale, V.; Vovk, I.; Walter, R.; Will, M.; Wunderlich, C.; Yamamoto, T.; Zarić, D.. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 1432-0746. - (2022). [10.48550/arXiv.2211.15321]