Issue |
A&A
Volume 695, March 2025
|
|
---|---|---|
Article Number | A152 | |
Number of page(s) | 18 | |
Section | Astrophysical processes | |
DOI | https://doi.org/10.1051/0004-6361/202452447 | |
Published online | 14 March 2025 |
Detection of RS Oph with LST-1 and modelling of its HE/VHE gamma-ray emission
1
Department of Physics, Tokai University, 4-1-1, Kita-Kaname, Hiratsuka, Kanagawa 259-1292, Japan
2
Institute for Cosmic Ray Research, University of Tokyo, 5-1-5, Kashiwa-no-ha, Kashiwa, Chiba 277-8582, Japan
3
INFN and Università degli Studi di Siena, Dipartimento di Scienze Fisiche, della Terra e dell’Ambiente (DSFTA), Sezione di Fisica, Via Roma 56, 53100 Siena, Italy
4
Université Paris-Saclay, Université Paris Cité, CEA, CNRS, AIM, F-91191 Gif-sur-Yvette Cedex, France
5
FSLAC IRL 2009, CNRS/IAC, La Laguna, Tenerife, Spain
6
Departament de Física Quàntica i Astrofísica, Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès, 1, 08028 Barcelona, Spain
7
Instituto de Astrofísica de Andalucía-CSIC, Glorieta de la Astronomía s/n, 18008 Granada, Spain
8
Department of Astronomy, University of Geneva, Chemin d’Ecogia 16, CH-1290 Versoix, Switzerland
9
IPARCOS-UCM, Instituto de Física de Partículas y del Cosmos, and EMFTEL Department, Universidad Complutense de Madrid, Plaza de Ciencias, 1. Ciudad Universitaria, 28040 Madrid, Spain
10
INFN Sezione di Napoli, Via Cintia, ed. G, 80126 Napoli, Italy
11
INAF – Osservatorio Astronomico di Roma, Via di Frascati 33, 00040 Monteporzio Catone, Italy
12
Max-Planck-Institut für Physik, Föhringer Ring 6, 80805 München, Germany
13
INFN Sezione di Padova and Università degli Studi di Padova, Via Marzolo 8, 35131 Padova, Italy
14
Univ. Savoie Mont Blanc, CNRS, Laboratoire d’Annecy de Physique des Particules – IN2P3, 74000 Annecy, France
15
Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany
16
Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
17
Faculty of Science and Technology, Universidad del Azuay, Cuenca, Ecuador
18
Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, RJ 22290-180 Rio de Janeiro, Brazil
19
Instituto de Astrofísica de Canarias and Departamento de Astrofísica, Universidad de La Laguna, C. Vía Láctea, s/n, 38205 La Laguna, Santa Cruz de Tenerife, Spain
20
CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
21
University of Geneva – Département de physique nucléaire et corpusculaire, 24 Quai Ernest Ansernet, 1211 Genève 4, Switzerland
22
INFN Sezione di Bari and Politecnico di Bari, Via Orabona 4, 70124 Bari, Italy
23
Institut de Fisica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra, (Barcelona), Spain
24
INAF – Osservatorio Astronomico di Brera, Via Brera 28, 20121 Milano, Italy
25
Faculty of Physics and Applied Informatics, University of Lodz, ul. Pomorska 149-153, 90-236 Lodz, Poland
26
INAF – Osservatorio di Astrofisica e Scienza dello spazio di Bologna, Via Piero Gobetti 93/3, 40129 Bologna, Italy
27
Lamarr Institute for Machine Learning and Artificial Intelligence, 44227 Dortmund, Germany
28
INFN Sezione di Trieste and Università degli studi di Udine, Via delle scienze 206, 33100 Udine, Italy
29
INFN Sezione di Catania, Via S. Sofia 64, 95123 Catania, Italy
30
INAF – Istituto di Astrofisica e Planetologia Spaziali (IAPS), Via del Fosso del Cavaliere 100, 00133 Roma, Italy
31
Aix Marseille Univ, CNRS/IN2P3, CPPM, Marseille, France
32
University of Alcalá UAH, Departamento de Physics and Mathematics, Pza. San Diego, 28801 Alcalá de Henares, Madrid, Spain
33
INFN Sezione di Bari and Università di Bari, Via Orabona 4, 70126 Bari, Italy
34
INFN Sezione di Torino, Via P. Giuria 1, 10125 Torino, Italy
35
Dipartimento di Fisica – Universitá degli Studi di Torino, Via Pietro Giuria 1, 10125 Torino, Italy
36
Palacky University Olomouc, Faculty of Science, 17. listopadu 1192/12, 771 46 Olomouc, Czech Republic
37
Dipartimento di Fisica e Chimica “E. Segrè”, Università degli Studi di Palermo, Via Archirafi 36, 90123 Palermo, Italy
38
IRFU, CEA, Université Paris-Saclay, Bât 141, 91191 Gif-sur-Yvette, France
39
Port d’Informació Científica, Edifici D, Carrer de l’Albareda, 08193 Bellaterrra, (Cerdanyola del Vallès), Spain
40
INFN Sezione di Bari, Via Orabona 4, 70125 Bari, Italy
41
Department of Physics, TU Dortmund University, Otto-Hahn-Str. 4, 44227 Dortmund, Germany
42
University of Rijeka, Department of Physics, Radmile Matejcic 2, 51000 Rijeka, Croatia
43
Institute for Theoretical Physics and Astrophysics, Universität Würzburg, Campus Hubland Nord, Emil-Fischer-Str. 31, 97074 Würzburg, Germany
44
Department of Physics and Astronomy, University of Turku, Finland, FI-20014 University of Turku, Finland
45
INFN Sezione di Roma La Sapienza, P.le Aldo Moro, 2, 00185 Rome, Italy
46
ILANCE, CNRS – University of Tokyo International Research Laboratory, University of Tokyo, 5-1-5 Kashiwa-no-Ha Kashiwa City, Chiba 277-8582, Japan
47
Physics Program, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8526, Japan
48
INFN Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
49
University of Split, FESB, R. Boškovića 32, 21000 Split, Croatia
50
Department of Physics, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi 990-8560, Japan
51
Institut für Theoretische Physik, Lehrstuhl IV: Plasma-Astroteilchenphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
52
Sendai College, National Institute of Technology, 4-16-1 Ayashi-Chuo, Aoba-ku, Sendai city, Miyagi 989-3128, Japan
53
Josip Juraj Strossmayer University of Osijek, Department of Physics, Trg Ljudevita Gaja 6, 31000 Osijek, Croatia
54
INFN Dipartimento di Scienze Fisiche e Chimiche – Università degli Studi dell’Aquila and Gran Sasso Science Institute, Via Vetoio 1, Viale Crispi 7, 67100 L’Aquila, Italy
55
Chiba University, 1-33, Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan
56
Kitashirakawa Oiwakecho, Sakyo Ward, Kyoto 606-8502, Japan
57
FZU – Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Praha 8, Czech Republic
58
Laboratory for High Energy Physics, École Polytechnique Fédérale, CH-1015 Lausanne, Switzerland
59
Astronomical Institute of the Czech Academy of Sciences, Bocni II 1401, 14100 Prague, Czech Republic
60
Faculty of Science, Ibaraki University, 2 Chome-1-1 Bunkyo, Mito, Ibaraki 310-0056, Japan
61
Faculty of Science and Engineering, Waseda University, 3 Chome-4-1 Okubo, Shinjuku City, Tokyo 169-0072, Japan
62
Sorbonne Université, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Energies, LPNHE, 4 place Jussieu, 75005 Paris, France
63
Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801, Japan
64
INFN Sezione di Trieste and Università degli Studi di Trieste, Via Valerio 2 I, 34127 Trieste, Italy
65
Escuela Politécnica Superior de Jaén, Universidad de Jaén, Campus Las Lagunillas s/n, Edif. A3, 23071 Jaén, Spain
66
Saha Institute of Nuclear Physics, Sector 1, AF Block, Bidhan Nagar, Bidhannagar, Kolkata, West Bengal 700064, India
67
Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 boul. Tsarigradsko chaussee, 1784 Sofia, Bulgaria
68
Dipartimento di Fisica e Astronomia (DIFA) Augusto Righi, Università di Bologna, Via Gobetti 93/2, I-40129 Bologna, Italy
69
Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, SC 29634, USA
70
Dipartimento di Fisica e Chimica ‘E. Segrè’ Università degli Studi di Palermo, Via delle Scienze, 90128 Palermo, Italy
71
Grupo de Electronica, Universidad Complutense de Madrid, Av. Complutense s/n, 28040 Madrid, Spain
72
Institute of Space Sciences (ICE, CSIC), and Institut d’Estudis Espacials de Catalunya (IEEC), and Institució Catalana de Recerca I Estudis Avançats (ICREA), Campus UAB, Carrer de Can Magrans, s/n, 08193 Bellatera, Spain
73
Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
74
School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 228-8555, Japan
75
RIKEN, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
76
Charles University, Institute of Particle and Nuclear Physics, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
77
Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
78
Institute for Space-Earth Environmental Research, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
79
Kobayashi-Maskawa Institute (KMI) for the Origin of Particles and the Universe, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
80
Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minamijosanjima, Tokushima 770-8506, Japan
81
INFN Sezione di Pisa, Edificio C – Polo Fibonacci, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
82
INFN Dipartimento di Scienze Fisiche e Chimiche – Università degli Studi dell’Aquila and Gran Sasso Science Institute, Via Vetoio 1, Viale Crispi 7, 67100 L’Aquila, Italy
83
Gifu University, Faculty of Engineering, 1-1 Yanagido, Gifu 501-1193, Japan
84
Department of Physical Sciences, Aoyama Gakuin University, Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
85
Graduate School of Science and Engineering, Saitama University, 255 Simo-Ohkubo, Sakura-ku, Saitama city, Saitama 338-8570, Japan
86
Department of Physics, Konan University, 8-9-1 Okamoto, Higashinada-ku Kobe 658-8501, Japan
⋆ Corresponding authors; lst-contact@cta-observatory.org
Received:
1
October
2024
Accepted:
15
January
2025
Context. The recurrent nova RS Ophiuchi (RS Oph) underwent a thermonuclear eruption in August 2021. In this event, RS Oph was detected by the High Energy Stereoscopic System (H.E.S.S.), the Major Atmospheric Gamma Imaging Cherenkov (MAGIC), and the first Large-Sized Telescope (LST-1) of the future Cherenkov Telescope Array Observatory (CTAO) at very-high gamma-ray energies above 100 GeV. This means that novae are a new class of very-high-energy (VHE) gamma-ray emitters.
Aims. We report the analysis of the RS Oph observations with LST-1. We constrain the particle population that causes the observed emission in hadronic and leptonic scenarios. Additionally, we study the prospects of detecting further novae using LST-1 and the upcoming LST array of CTAO-North.
Methods. We conducted target-of-opportunity observations with LST-1 from the first day of this nova event. The data were analysed in the framework of cta-lstchain and Gammapy, the official CTAO-LST reconstruction and analysis packages. One-zone hadronic and leptonic models were considered to model the gamma-ray emission of RS Oph using the spectral information from Fermi-LAT and LST-1, together with public data from the MAGIC and H.E.S.S. telescopes.
Results. RS Oph was detected at 6.6σ with LST-1 in the first 6.35 hours of observations following the eruption. The hadronic scenario is preferred over the leptonic scenario considering a proton energy spectrum with a power-law model with an exponential cutoff whose position increases from (0.26 ± 0.08) TeV on day 1 up to (1.6 ± 0.6) TeV on day 4 after the eruption. The deep sensitivity and low energy threshold of the LST-1/LST array will allow us to detect faint novae and increase their discovery rate.
Key words: radiation mechanisms: non-thermal / binaries: close / binaries: symbiotic / novae / cataclysmic variables / stars: individual: RS Ophiuchi / gamma rays: stars
© The Authors 2025
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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