Constraining the TeV gamma-ray emission of SN 2024bch, a possible type IIn-L from a red supergiant progenitor

Multiwavelength observations and analysis of the progenitor

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 INFN Sezione di Napoli, Via Cintia, ed. G, 80126 Napoli, Italy
¹⁰ INAF – Osservatorio Astronomico di Roma, Via di Frascati 33, 00040 Monteporzio Catone, Italy
¹¹ Max-Planck-Institut für Physik, Boltzmannstraße 8, 85748 Garching bei München, Germany
¹² INFN Sezione di Padova and Università degli Studi di Padova, Via Marzolo 8, 35131 Padova, Italy
¹³ 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
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 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
¹⁸ Faculty of Science and Technology, Universidad del Azuay, Cuenca, Ecuador
¹⁹ Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, RJ, 22290-180 Rio de Janeiro, Brazil
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 Dipartimento di Fisica e Astronomia (DIFA) Augusto Righi, Università di Bologna, via Gobetti 93/2, I-40129 Bologna, Italy
²⁸ Lamarr Institute for Machine Learning and Artificial Intelligence, 44227 Dortmund, Germany
²⁹ INFN Sezione di Trieste and Università degli studi di Udine, Via delle scienze 206, 33100 Udine, 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 delle Scienze, 90128 Palermo, Italy
³⁸ INFN Sezione di Catania, Via S. Sofia 64, 95123 Catania, Italy
³⁹ IRFU, CEA, Université Paris-Saclay, Bât 141, 91191 Gif-sur-Yvette, France
⁴⁰ Port d’Informació Científica, Edifici D, Carrer de l’Albareda, 08193 Bellaterrra (Cerdanyola del Vallès), Spain
⁴¹ INFN Sezione di Bari, Via Orabona 4, 70125 Bari, Italy
⁴² Department of Physics, TU Dortmund University, Otto-Hahn-Str. 4, 44227 Dortmund, Germany
⁴³ University of Rijeka, Department of Physics, Radmile Matejcic 2, 51000 Rijeka, Croatia
⁴⁴ Institute for Theoretical Physics and Astrophysics, Universität Würzburg, Campus Hubland Nord, Emil-Fischer-Str. 31, 97074 Würzburg, Germany
⁴⁵ Department of Physics and Astronomy, University of Turku, Finland, FI-20014 University of Turku, Finland
⁴⁶ Department of Physics, TU Dortmund University, Otto-Hahn-Str. 4, 44227 Dortmund, Germany
⁴⁷ INFN Sezione di Roma La Sapienza, P.le Aldo Moro, 2, 00185 Rome, Italy
⁴⁸ ILANCE, CNRS – University of Tokyo International Research Laboratory, University of Tokyo, 5-1-5 Kashiwa-no-Ha Kashiwa City, Chiba 277-8582, Japan
⁴⁹ Physics Program, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima City, Hiroshima 739-8526, Japan
⁵⁰ INFN Sezione di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
⁵¹ University of Split, FESB, R. Boškovića 32, 21000 Split, Croatia
⁵² Department of Physics, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi 990-8560, Japan
⁵³ Institut für Theoretische Physik, Lehrstuhl IV: Plasma-Astroteilchenphysik, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany
⁵⁴ Sendai College, National Institute of Technology, 4-16-1 Ayashi-Chuo, Aoba-ku, Sendai city, Miyagi 989-3128, Japan
⁵⁵ Josip Juraj Strossmayer University of Osijek, Department of Physics, Trg Ljudevita Gaja 6, 31000 Osijek, Croatia
⁵⁶ Department of Astronomy and Space Science, Chungnam National University, Daejeon 34134, Republic of Korea
⁵⁷ 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
⁵⁸ Chiba University, 1-33, Yayoicho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan
⁵⁹ Kitashirakawa Oiwakecho, Sakyo Ward, Kyoto 606-8502, Japan
⁶⁰ FZU – Institute of Physics of the Czech Academy of Sciences, Na Slovance 1999/2, 182 21 Praha 8, Czech Republic
⁶¹ Laboratory for High Energy Physics, École Polytechnique Fédérale, CH-1015 Lausanne, Switzerland
⁶² Astronomical Institute of the Czech Academy of Sciences, Bocni II 1401, 14100 Prague, Czech Republic
⁶³ Faculty of Science, Ibaraki University, 2 Chome-1-1 Bunkyo, Mito, Ibaraki 310-0056, Japan
⁶⁴ Sorbonne Université, CNRS/IN2P3, Laboratoire de Physique Nucléaire et de Hautes Energies, LPNHE, 4 place Jussieu, 75005 Paris, France
⁶⁵ Graduate School of Science and Engineering, Saitama University, 255 Simo-Ohkubo, Sakura-ku, Saitama city, Saitama 338-8570, Japan
⁶⁶ Institute of Particle and Nuclear Studies, KEK (High Energy Accelerator Research Organization), 1-1 Oho, Tsukuba 305-0801, Japan
⁶⁷ INFN Sezione di Trieste and Università degli Studi di Trieste, Via Valerio 2 I, 34127 Trieste, Italy
⁶⁸ Escuela Politécnica Superior de Jaén, Universidad de Jaén, Campus Las Lagunillas s/n, Edif. A3, 23071 Jaén, Spain
⁶⁹ Saha Institute of Nuclear Physics, Sector 1, AF Block, Bidhan Nagar, Bidhannagar, Kolkata, West Bengal 700064, India
⁷⁰ Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 boul. Tsarigradsko chaussee, 1784 Sofia, Bulgaria
⁷¹ Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, SC 29634, USA
⁷² Institut de Fisica d’Altes Energies (IFAE), The Barcelona Institute of Science and Technology, Campus UAB, 08193 Bellaterra (Barcelona), Spain
⁷³ Grupo de Electronica, Universidad Complutense de Madrid, Av. Complutense s/n, 28040 Madrid, Spain
⁷⁴ 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
⁷⁵ Department of Physics, Konan University, 8-9-1 Okamoto, Higashinada-ku Kobe 658-8501, Japan
⁷⁶ School of Allied Health Sciences, Kitasato University, Sagamihara, Kanagawa 228-8555, Japan
⁷⁷ RIKEN, Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
⁷⁸ Charles University, Institute of Particle and Nuclear Physics, V Holešovičkách 2, 180 00 Prague 8, Czech Republic
⁷⁹ Division of Physics and Astronomy, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
⁸⁰ Institute for Space-Earth Environmental Research, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
⁸¹ Kobayashi-Maskawa Institute (KMI) for the Origin of Particles and the Universe, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
⁸² Graduate School of Technology, Industrial and Social Sciences, Tokushima University, 2-1 Minamijosanjima, Tokushima 770-8506, Japan
⁸³ INFN Sezione di Pisa, Edificio C – Polo Fibonacci, Largo Bruno Pontecorvo 3, 56127 Pisa, Italy
⁸⁴ Gifu University, Faculty of Engineering, 1-1 Yanagido, Gifu 501-1193, Japan
⁸⁵ Department of Physical Sciences, Aoyama Gakuin University, Fuchinobe, Sagamihara, Kanagawa 252-5258, Japan
⁸⁶ Macroarea di Scienze MMFFNN, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy

^⋆ Corresponding authors: lst-contact@cta-observatory.org

Received: 24 March 2025
Accepted: 30 July 2025

Abstract

We present very high-energy optical photometry and spectroscopic observations of SN 2024bch in the nearby galaxy NGC 3206 (∼20 Mpc). We used gamma-ray observations performed with the first Large-Sized Telescope (LST-1) of the Cherenkov Telescope Array Observatory (CTAO) and optical observations with the Liverpool Telescope (LT) combined with data from public repositories to evaluate the general properties of the event and the progenitor star. No significant emission above the LST-1 energy threshold for this observation (∼100 GeV) was detected in the direction of SN 2024bch, and we computed an integral upper limit on the photon flux of F_γ(> 100 GeV)≤3.61 × 10⁻¹² cm⁻² s⁻¹ based on six nonconsecutive nights of observations with the LST-1, between 16 and 38 days after the explosion. Employing a general model for the gamma-ray flux emission, we found an upper limit on the mass-loss-rate to wind-velocity ratio of Ṁ/u_w ≤ 10⁻⁴ M_⊙/ yr  s/km, although gamma-gamma absorption could potentially have skewed this estimation, effectively weakening our constraint. From spectro-photometric observations we found progenitor parameters of M_pr = 11 – 20 M_⊙ and R_pr = 531 ± 125 R_⊙. Finally, using archival images from the Hubble Space Telescope, we constrained the luminosity of the progenitor star to log (L_pr/L_⊙) ≤ 4.82 and its effective temperature to T_pr ≤ 4000 K. Our results suggest that SN 2024bch is a type IIn-L supernova that originated from a progenitor star consistent with a red supergiant. We show how the correct estimation of the mass-loss history of a supernova will play a major role in future multiwavelength observations.