Detection of very high-energy gamma-ray emission from Eta Carinae during its 2020 periastron passage

The colliding-wind binary system η Carinae has been identified as a source of high-energy (HE, below ∼100 GeV) and very high-energy (VHE, above ∼100 GeV) gamma rays in the last decade, making it unique among these systems. With its eccentric 5.5-year-long orbit, the periastron passage, during which the stars are separated by only 1–2 au, is an intriguing time interval to probe particle acceleration processes within the system. In this work, we report on an extensive VHE observation campaign that for the first time covers the full periastron passage carried out with the High Energy Stereoscopic System (H.E.S.S.) in its 5-telescope configuration with upgraded cameras. The VHE gamma-ray emission from η Carinae was detected during the periastron passage with a steep spectrum with the spectral index Γ = 3.3 ± 0.2 stat ± 0.1 syst . Together with previous and follow-up observations, we derive a long-term light curve sampling one full orbit, showing hints of an increase in the VHE flux towards periastron, but no hint of variability during the passage itself. An analysis of contemporaneous Fermi-LAT data shows that the VHE spectrum represents a smooth continuation of the HE spectrum. From modelling the combined spectrum, we conclude that the gamma-ray emission region is located at distances of ∼10–20 au from the centre of mass of the system and that protons are accelerated up to energies of at least several tera-electronvolts inside the system in this phase.

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Journal
Astronomy and Astrophysics
Published
2025-02-01
DOI
https://doi.org/10.1051/0004-6361/202453052
Citations
3
Primary Topic
Gamma-ray bursts and supernovae
Type
article
Field-Weighted Citation Impact
3.46

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Detection of very high-energy gamma-ray emission from Eta Carinae during its 2020 periastron passage

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Detection of very high-energy gamma-ray emission from Eta Carinae during its 2020 periastron passage

J. Bolmont, D. Berge, Lucia Haerer, S. M. Caballero‐Nieves, F. Schüßler, J. A. Hinton, Miroslav D Filipović, Quentin Rémy, G. Rowell, S. Ravikularaman, T. L. Holch, Mathieu de Bony de Lavergne, D. Horns, Rukaiya Khatoon, R. D. Parsons, M. Vecchi, F. Brun, A. Wierzcholska, Brian Reville, C. Venter, T. Chand, W. Hofmann, G. Cotter, B. Khélifi, K. Egberts, Helena X. Ren, S. Casanova, B. A. Hess, S. Chandra, E. Ruiz-Velasco, M. de Naurois, A. Mitchell, H. M. Schutte, O. Chibueze, K. Bernlöhr, W. Kluźniak, Laura Olivera-Nieto, H. Salzmann, Jonathan Mackey, J. Aschersleben, V. Barbosa Martins, Naomi Tsuji, J. Damascene Mbarubucyeye, R. White, M. Jamrozy, J. F. Glicenstein, O. Reimer, M. Cerruti, R.G. Lang, S. Gabici, R. Steenkamp, M. Sasaki, V. Marandon, Zhi-Qiu Huang, A. Santangelo, Sebastian Funk, G. Grolleron, C. van Eldik, A. Jardin-Blicq, C. Burger-Scheidlin, F. Bradascio, Halim Ashkar, S. Spencer, R. Moderski, L. Mohrmann, A. M. Brown, Tiffany Collins, James O. Chibueze, J. N. S. Shapopi, Kirsty Feijen, M. Holler, M. Tsirou, J.-P. Lenain, D. Kostunin, F. Aharonian, T. Tanaka, Rowan William Batzofin, A. A. Zdziarski, S. Steinmassl, K. Kosack, B. Rudak, A. Quirrenbach, T. Wach, Nu. Komin, Sebastian Panny, G. Martí-Devesa, Karim Sabri, U. Pensec, Maxime Regeard, A. Chen, J. I. Djuvsland, A. Zech, M.-H. Grondin, F. Ait Benkhali, S. J. Wagner, E. Moulin, M. Böttcher, C. Boisson, F. Jankowsky, Ł. Stawarz, J.-P. Ernenwein, S. Ohm, F. Rieger, R. Marx, A. Lemière, A. Reimer, J. Niemiec, S. Einecke, D. Malyshev, R. Brose, E. de Ona Wilhelmi, M. Ostrowski, G. Fontaine, N. Żywucka, I. Jung-Richardt, M. Panter, C. Steppa, V. Sahakian, A. Mehta, F. Werner, M. Lemoine-Goumard, G. Pühlhofer, S. Le Stum, A. Luashvili, Y. Becherini, M. Zacharias, J. Devin, A. Dmytriiev, R. Terrier, Johannes Schäfer, M. Tluczykont, B. Bruno, A. Djannati-Ataı̈, M. O. Moghadam, K. Streil, A. Marcowith, K. Katarzyński, J. de Assis Scarpin
article en
3 citations

Abstract

The colliding-wind binary system η Carinae has been identified as a source of high-energy (HE, below ∼100 GeV) and very high-energy (VHE, above ∼100 GeV) gamma rays in the last decade, making it unique among these systems. With its eccentric 5.5-year-long orbit, the periastron passage, during which the stars are separated by only 1–2 au, is an intriguing time interval to probe particle acceleration processes within the system. In this work, we report on an extensive VHE observation campaign that for the first time covers the full periastron passage carried out with the High Energy Stereoscopic System (H.E.S.S.) in its 5-telescope configuration with upgraded cameras. The VHE gamma-ray emission from η Carinae was detected during the periastron passage with a steep spectrum with the spectral index Γ = 3.3 ± 0.2 stat ± 0.1 syst . Together with previous and follow-up observations, we derive a long-term light curve sampling one full orbit, showing hints of an increase in the VHE flux towards periastron, but no hint of variability during the passage itself. An analysis of contemporaneous Fermi-LAT data shows that the VHE spectrum represents a smooth continuation of the HE spectrum. From modelling the combined spectrum, we conclude that the gamma-ray emission region is located at distances of ∼10–20 au from the centre of mass of the system and that protons are accelerated up to energies of at least several tera-electronvolts inside the system in this phase.

Astronomy and AstrophysicsVol. 694
Jagiellonian University (PL), Centre National de la Recherche Scientifique (FR), Dublin Institute For Advanced Studies (IE), A. Alikhanyan National Laboratory (AM), École Polytechnique (FR), Universität Hamburg (DE), Konan University (JP), University of Groningen (NL), University of Potsdam (DE), Friedrich-Alexander-Universität Erlangen-Nürnberg (DE), Universität Innsbruck (AT), University of the Witwatersrand (ZA), Yerevan State University (AM), Université de Montpellier (FR), Université Paris Cité (FR), Aix-Marseille Université (FR), University of Namibia (NA), Linnaeus University (SE), Heidelberg University (DE), Commissariat à l'Énergie Atomique et aux Énergies Alternatives (FR), Université Paris Sciences et Lettres (FR), North-West University (ZA), Université Paris-Saclay (FR), Deutsches Elektronen-Synchrotron DESY (DE), Laboratoire AstroParticule et Cosmologie (FR), Nicolaus Copernicus University (PL), Humboldt-Universität zu Berlin (DE), Sorbonne Université (FR), University of Oxford (GB), Janssen (France) (FR), Laboratoire Univers et Théories (FR), Centre de physique des particules de Marseille (FR), Laboratoire Univers et Particules de Montpellier (FR), Laboratoire de Physique Nucléaire et de Hautes Énergies (FR), Institute of Nuclear Physics, Polish Academy of Sciences (PL), Nippon Soken (Japan) (JP), RIKEN (JP), Laboratoire de Physique des deux infinis Bordeaux (FR), CEA Paris-Saclay (FR), Institut National de Physique Nucléaire et de Physique des Particules (FR), Nicolaus Copernicus Astronomical Center (PL), Laboratoire Leprince-Ringuet (FR), Max Planck Institute for Nuclear Physics (DE), Institut de Recherche sur les Lois Fondamentales de l'Univers (FR), The University of Adelaide (AU), Western Sydney University (AU), University of Tübingen (DE), Polish Academy of Sciences (PL)
Department of Science and Innovation, South Africa, National Research Foundation, Science Foundation Ireland, Universiteit van Amsterdam, Irish Research Council, Bundesministerium für Bildung und Forschung, Austrian Science Fund, Max-Planck-Gesellschaft, Centre National de la Recherche Scientifique, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, National Commission on Research, Science and Technology, University of Namibia, Bundesministerium für Bildung, Wissenschaft und Forschung, Science and Technology Facilities Council, Japan Society for the Promotion of Science, Institut National de Physique Nucléaire et de Physique des Particules
Openalex Percentile: Top 9%
Gamma-ray bursts and supernovae
3.46
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