Abstract
Gamma-ray observations have established energetic isolated pulsars as outstanding particle accelerators and antimatter factories. However, many questions are still open regarding the acceleration and radiation processes involved, as well as the locations where they occur. The radiation spectra of all gamma-ray pulsars observed to date show strong cutoffs or a break above energies of a few gigaelectronvolts. Using the High Energy Stereoscopic System’s Cherenkov telescopes, we discovered a radiation component from the Vela pulsar which emerges beyond this generic cutoff and extends up to energies of at least 20 teraelectronvolts. This is an order of magnitude larger than in the case of the Crab pulsar, the only other pulsar detected in the teraelectronvolt energy range. Our results challenge the state-of-the-art models for the high-energy emission of pulsars. Furthermore, they pave the way for investigating other pulsars through their multiteraelectronvolt emission, thereby imposing additional constraints on the acceleration and emission processes in their extreme energy limit.
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Data availability
The H.E.S.S. raw data used in this study are not public but belong to the H.E.S.S. Collaboration. The high-level data for the light curve (Fig. 1), and the confidence interval for the spectral energy distributions (Fig. 3) are available at: https://www.mpi-hd.mpg.de/hfm/HESS/pages/publications/auxiliary/2023_Vela_MultiTeV.
Change history
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Acknowledgements
The support of the Namibian authorities and of the University of Namibia in facilitating the construction and operation of H.E.S.S. is gratefully acknowledged, as is the support by the German Ministry for Education and Research (BMBF), the Max Planck Society, the German Research Foundation (DFG), the Helmholtz Association, the Alexander von Humboldt Foundation, the French Ministry of Higher Education, Research and Innovation, the Centre National de la Recherche Scientifique (CNRS/IN2P3 and CNRS/INSU), the Commissariat à l’énergie atomique et aux énergies alternatives (CEA), the UK Science and Technology Facilities Council (STFC), the Irish Research Council (IRC) and the Science Foundation Ireland (SFI), the Knut and Alice Wallenberg Foundation, the Polish Ministry of Education and Science (agreement no. 2021/WK/06), the South African Department of Science and Technology and National Research Foundation, the National Commission on Research, Science & Technology of Namibia (NCRST), the Austrian Federal Ministry of Education, Science and Research and the Austrian Science Fund (FWF), the Australian Research Council (ARC), the Japan Society for the Promotion of Science, the University of Amsterdam and the Science Committee of Armenia (grant no. 21AG-1C085). Work at NRL is supported by NASA. We appreciate the excellent work of the technical support staff in Berlin, Zeuthen, Heidelberg, Palaiseau, Paris, Saclay, Tübingen and in Namibia in the construction and operation of the equipment. This work benefited from services provided by the H.E.S.S. Virtual Organization supported by the national resource providers of the EGI Federation. This research made use of the Python packages Astropy96 and naima97. A.D.-A. thanks B. Cerutti and J. Pétri for fruitful discussions on the striped-wind model during the ‘Entretiens sur l’observation et la modélisation des pulsars’ sessions funded by the Programme National Hautes Energies; that support is acknowledged here. The authors wish to acknowledge the seminal role played by our late colleague, O. de Jager, in opening the VHE pulsar window of research.
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A.D.-A. led the H.E.S.S. project of the Vela pulsar and the main H.E.S.S. data analysis. G. Giavitto and L.M. performed the cross-check analyses used in this study along with V.M. The statistical assessment of the results relies on MC simulations performed by M.S.-J. A.D.-A. developed the interpretation and modelling together with B.R., M.S.-J., T. Tavernier, E.d.O.W. and C.V. The manuscript was prepared by A.D.-A., B.R., E.d.O.W., C.V. and L.M. T.L. and M. Böttcher supervised the review and discussion of the manuscript among the coauthors. The sketch in Fig. 4 was designed by H.P. together with E.d.O.W., based on an initial proposal by M.S.-J. and A.D.-A. The other coauthors contributed by preparing and obtaining the observations; by calibrating the data, simulating showers and developing analyses; by developing, constructing, operating and maintaining telescopes, cameras and calibration devices; and by conducting data handling, data reduction and data analysis. The ephemeris used for phase-folding the H.E.S.S. data was provided by M.K., S.J., R.M.S. and D.A. Smith. All authors meet the journal’s authorship criteria and have reviewed, discussed and commented on the results and the manuscript.
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The H.E.S.S. Collaboration et al.. Discovery of a radiation component from the Vela pulsar reaching 20 teraelectronvolts. Nat Astron 7, 1341–1350 (2023). https://doi.org/10.1038/s41550-023-02052-3
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DOI: https://doi.org/10.1038/s41550-023-02052-3
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