Acceleration of petaelectronvolt protons in the Galactic Centre
Creators: name: collaboration, H. E. S. S.
name: :
name: Abramowski, A.
name: Aharonian, F.
name: Benkhali, F. Ait
name: Akhperjanian, A. G.
name: Angüner, E. O.
name: Backes, M.
name: Balzer, A.
name: Becherini, Y.
name: Tjus, J. Becker
name: Berge, D.
name: Bernhard, S.
name: Bernlöhr, K.
name: Birsin, E.
name: Blackwell, R.
name: Böttcher, M.
name: Boisson, C.
name: Bolmont, J.
name: Bordas, P.
name: Bregeon, J.
name: Brun, F.
name: Brun, P.
name: Bryan, M.
name: Bulik, T.
name: Carr, J.
name: Casanova, S.
name: Chakraborty, N.
name: Chalme-Calvet, R.
name: Chaves, R. C. G.
name: Chen, A.
name: Chrétien, M.
name: Colafrancesco, S.
name: Cologna, G.
name: Conrad, J.
name: Couturier, C.
name: Cui, Y.
name: Davids, I. D.
name: Degrange, B.
name: Deil, C.
name: deWilt, P.
name: Djannati-Ataï, A.
name: Domainko, W.
name: Donath, A.
name: Drury, L. O'C.
name: Dubus, G.
name: Dutson, K.
name: Dyks, J.
name: Dyrda, M.
name: Edwards, T.
name: Egberts, K.
name: Eger, P.
name: Ernenwein, J. -P.
name: Espigat, P.
name: Farnier, C.
name: Fegan, S.
name: Feinstein, F.
name: Fernandes, M. V.
name: Fernandez, D.
name: Fiasson, A.
name: Fontaine, G.
name: Förster, A.
name: Füßling, M.
name: Gabici, S.
name: Gajdus, M.
name: Gallant, Y. A.
name: Garrigoux, T.
name: Giavitto, G.
name: Giebels, B.
name: Glicenstein, J. F.
name: Gottschall, D.
name: Goyal, A.
name: Grondin, M. -H.
name: Grudzińska, M.
name: Hadasch, D.
name: Häffner, S.
name: Hahn, J.
name: Hawkes, J.
name: Heinzelmann, G.
name: Henri, G.
name: Hermann, G.
name: Hervet, O.
name: Hillert, A.
name: Hinton, J. A.
name: Hofmann, W.
name: Hofverberg, P.
name: Hoischen, C.
name: Holler, M.
name: Horns, D.
name: Ivascenko, A.
name: Jacholkowska, A.
name: Jamrozy, M.
name: Janiak, M.
name: Jankowsky, F.
name: Jung-Richardt, I.
name: Kastendieck, M. A.
name: Katarzyński, K.
name: Katz, U.
name: Kerszberg, D.
name: Khélifi, B.
name: Kieffer, M.
name: Klepser, S.
name: Klochkov, D.
name: Kluźniak, W.
name: Kolitzus, D.
name: Komin, Nu.
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name: Krüger, P. P.
name: Laffon, H.
name: Lamanna, G.
name: Lau, J.
name: Lefaucheur, J.
name: Lefranc, V.
name: Lemiére, A.
name: Lemoine-Goumard, M.
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name: Mitchell, A. M. W.
name: Moderski, R.
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name: de Naurois, M.
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name: Panter, M.
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name: Pekeur, N. W.
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name: Petrucci, P. -O.
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name: Reimer, A.
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name: Reyes, R. de los
name: Rieger, F.
name: Romoli, C.
name: Rosier-Lees, S.
name: Rowell, G.
name: Rudak, B.
name: Rulten, C. B.
name: Sahakian, V.
name: Salek, D.
name: Sanchez, D. A.
name: Santangelo, A.
name: Sasaki, M.
name: Schlickeiser, R.
name: Schüssler, F.
name: Schulz, A.
name: Schwanke, U.
name: Schwemmer, S.
name: Seyffert, A. S.
name: Simoni, R.
name: Sol, H.
name: Spanier, F.
name: Spengler, G.
name: Spies, F.
name: Stawarz, Ł.
name: Steenkamp, R.
name: Stegmann, C.
name: Stinzing, F.
name: Stycz, K.
name: Sushch, I.
name: Tavernet, J. -P.
name: Tavernier, T.
name: Taylor, A. M.
name: Terrier, R.
name: Tluczykont, M.
name: Trichard, C.
name: Tuffs, R.
name: Valerius, K.
name: van der Walt, J.
name: van Eldik, C.
name: van Soelen, B.
name: Vasileiadis, G.
name: Veh, J.
name: Venter, C.
name: Viana, A.
name: Vincent, P.
name: Vink, J.
name: Voisin, F.
name: Völk, H. J.
name: Vuillaume, T.
name: Wagner, S. J.
name: Wagner, P.
name: Wagner, R. M.
name: Weidinger, M.
name: Weitzel, Q.
name: White, R.
name: Wierzcholska, A.
name: Willmann, P.
name: Wörnlein, A.
name: Wouters, D.
name: Yang, R.
name: Zabalza, V.
name: Zaborov, D.
name: Zacharias, M.
name: Zdziarski, A. A.
name: Zech, A.
name: Zefi, F.
name: Żywucka, N.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Galactic cosmic rays reach energies of at least a few Peta-electronvolts (1 PeV =$10^\mathbf{15}$ electron volts). This implies our Galaxy contains PeV accelerators (PeVatrons), but all proposed models of Galactic cosmic-ray accelerators encounter non-trivial difficulties at exactly these energies. Tens of Galactic accelerators capable of accelerating particle to tens of TeV (1 TeV =$10^\mathbf{12}$ electron volts) energies were inferred from recent gamma-ray observations. None of the currently known accelerators, however, not even the handful of shell-type supernova remnants commonly believed to supply most Galactic cosmic rays, have shown the characteristic tracers of PeV particles: power-law spectra of gamma rays extending without a cutoff or a spectral break to tens of TeV. Here we report deep gamma-ray observations with arcminute angular resolution of the Galactic Centre regions, which show the expected tracer of the presence of PeV particles within the central 10~parsec of the Galaxy. We argue that the supermassive black hole Sagittarius A* is linked to this PeVatron. Sagittarius A* went through active phases in the past, as demonstrated by X-ray outbursts and an outflow from the Galactic Centre. Although its current rate of particle acceleration is not sufficient to provide a substantial contribution to Galactic cosmic rays, Sagittarius A* could have plausibly been more active over the last $\gtrsim 10^{6-7}$ years, and therefore should be considered as a viable alternative to supernova remnants as a source of PeV Galactic cosmic rays.
description: 29 pages, 7 figures, 3 tables, in press, for official published article see http://www.nature.com/nature/journal/v531/n7595/full/nature17147.html