Issue |
A&A
Volume 671, March 2023
|
|
---|---|---|
Article Number | A12 | |
Number of page(s) | 12 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361/202244931 | |
Published online | 28 February 2023 |
MAGIC observations provide compelling evidence of hadronic multi-TeV emission from the putative PeVatron SNR G106.3+2.7
1
Japanese MAGIC Group: Institute for Cosmic Ray Research (ICRR), The University of Tokyo,
Kashiwa,
277-8582
Chiba, Japan
2
Instituto de Astrofisica de Canarias and Dpto. de Astrofisica, Universidad de La Laguna,
38200
La Laguna, Tenerife, Spain
3
Instituto de Astrofisica de Andalucia-CSIC,
Glorieta de la Astronomia s/n,
18008
Granada, Spain
4
National Institute for Astrophysics (INAF),
00136
Rome, Italy
5
Università di Udine and INFN Trieste,
33100
Udine, Italy
6
Max-Planck-Institut für Physik,
80805
München, Germany
7
Università di Padova and INFN,
35131
Padova, Italy
8
Institut de Fisica d'Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST),
08193
Bellaterra (Barcelona), Spain
9
Technische Universität Dortmund,
44221
Dortmund, Germany
10
Croatian MAGIC Group: University of Zagreb, Faculty of Electrical Engineering and Computing (FER),
10000
Zagreb, Croatia
11
IPARCOS Institute and EMFTEL Department, Universidad Complutense de Madrid,
28040
Madrid, Spain
12
Centro Brasileiro de Pesquisas Físicas (CBPF),
22290-180
URCA, Rio de Janeiro (RJ), Brazil
13
University of Lodz, Faculty of Physics and Applied Informatics, Department of Astrophysics,
90-236
Lodz, Poland
14
Deutsches Elektronen-Synchrotron (DESY),
15738
Zeuthen, Germany
15
ETH Zürich,
8093
Zürich, Switzerland
16
Università di Pisa and INFN Pisa,
56126
Pisa, Italy
17
Universitat de Barcelona, ICCUB, IEEC-UB,
08028
Barcelona, Spain
18
Armenian MAGIC Group: A. Alikhanyan National Science Laboratory,
0036
Yerevan, Armenia
19
Centro de Investigaciones Energéticas, Medioambientales y Tecnologicas,
28040
Madrid, Spain
20
Department for Physics and Technology, University of Bergen,
5007
Bergen, Norway
21
INFN MAGIC Group: INFN Sezione di Catania and Dipartimento di Fisica e Astronomia, University of Catania,
95123
Catania, Italy
22
INFN MAGIC Group: INFN Sezione di Torino and Università degli Studi di Torino,
10125
Torino, Italy
23
INFN MAGIC Group: INFN Sezione di Bari and Dipartimento Interateneo di Fisica dell'Università e del Politecnico di Bari,
70125
Bari, Italy
24
Croatian MAGIC Group: University of Rijeka, Faculty of Physics,
51000
Rijeka, Croatia
25
Universität Würzburg,
97074
Würzburg, Germany
26
University of Geneva,
Chemin d'Ecogia 16,
1290
Versoix, Switzerland
27
Finnish MAGIC Group: Finnish Centre for Astronomy with ESO, University of Turku,
20014
Turku, Finland
28
Departament de Fisica, and CERES-IEEC, Universitat Autönoma de Barcelona,
08193
Bellaterra, Spain
29
Japanese MAGIC Group: Physics Program, Graduate School of Advanced Science and Engineering, Hiroshima University,
739-8526
Hiroshima, Japan
30
Armenian MAGIC Group: ICRANet-Armenia,
0019
Yerevan, Armenia
31
Croatian MAGIC Group: University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture (FESB),
21000
Split, Croatia
32
Croatian MAGIC Group: Josip Juraj Strossmayer University of Osijek, Department of Physics,
31000
Osijek, Croatia
33
Japanese MAGIC Group: Department of Physics, Tokai University,
Hiratsuka,
259-1292
Kanagawa, Japan
34
Università di Siena and INFN Pisa,
53100
Siena, Italy
35
Saha Institute of Nuclear Physics, A CI of Homi Bhabha National Institute,
Kolkata
700064,
West Bengal, India
36
Inst. for Nucl. Research and Nucl. Energy, Bulgarian Academy of Sciences,
1784
Sofia, Bulgaria
37
Japanese MAGIC Group: Department of Physics, Yamagata University,
Yamagata
990-8560, Japan
38
Finnish MAGIC Group: Space Physics and Astronomy Research Unit, University of Oulu,
90014
Oulu, Finland
39
Japanese MAGIC Group: Department of Physics, Kyoto University,
606-8502
Kyoto, Japan
40
Japanese MAGIC Group: Institute for Space-Earth Environmental Research and Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University,
464-6801
Nagoya, Japan
41
Croatian MAGIC Group: Ruđer Bošković Institute,
10000
Zagreb, Croatia
42
INFN MAGIC Group: INFN Sezione di Perugia,
06123
Perugia, Italy
43
INFN MAGIC Group: INFN Roma Tor Vergata,
00133
Roma, Italy
44
Japanese MAGIC Group: Department of Physics, Konan University,
Kobe, Hyogo
658-8501, Japan
45
International Center for Relativistic Astrophysics (ICRA),
Rome, Italy
46
Port d'Informacio Cientifica (PIC),
08193
Bellaterra (Barcelona), Spain
47
Ruhr-Universität Bochum, Fakultät für Physik und Astronomie, Astronomisches Institut (AIRUB),
44801
Bochum, Germany
48
University of Innsbruck, Institute for Astro- and Particle Physics, University of Innsbruck,
A-6020
Innsbruck, Austria
49
Dipartimento di Fisica, Università di Trieste,
34127
Trieste, Italy
50
University of Lodz, Faculty of Physics and Applied Informatics, Department of Astrophysics,
90-236
Lodz, Poland
Received:
9
September
2022
Accepted:
11
November
2022
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.
Key words: acceleration of particles / cosmic rays / gamma rays: general / gamma rays: ISM / ISM: clouds / ISM: supernova remnants
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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