Hassan E. Abdalla, A. Abramowski, Felix A. Aharonian, F. Ait Benkhali, Ekrem Oǧuzhan Angüner, M. Arakawa, C. Armand, M. Arrieta, M. Backes, A. Balzer, M. Barnard, Y. Becherini, J. Becker Tjus, D. Berge, S. Bernhard, K. Bernloehr, R. Blackwell, M. Bottcher, C. Boisson, J. Bolmont, S. Bonnefoy, Pol Bordas, J. Bregeon, F. Brun, P. Brun, M. Bryan, M. Buechele, T. Bulik, M. Capasso, S. Caroff, A. Carosi, Sabrina Casanova, M. Cerruti, N. Chakraborty, R. C. G. Chaves, A. Chen, J. Chevalier, S. Colafrancesco, B. Condon, J. Conrad, I. D. Davids, J. Decock, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Atai, A. Donath, J. Dyks, T. Edwards, Kathrin Egberts, G. Emery, J-P Ernenwein, S. Eschbach, C. Farnier, S. Fegan, M. Fernandes, A. Fiasson, G. Fontaine, S. Funk, M. Fuessling, S. Gabici, Y. A. Gallant, T. Garrigoux, F. Gate, G. Giavitto, D. Glawion, J. F. Glicenstein, D. Gottschall, M-H Grondin, J. Hahn, M. Haupt, J. Hawkes, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, W. Hofmann, Clemens Hoischen, T. L. Holch, M. Holler, D. Horns, A. Ivascenko, H. Iwasaki, A. Jacholkowska, M. Jamrozy, D. Jankowsky, F. Jankowsky, M. Jingo, L. Jouvin, I Jung-Richardt, M. A. Kastendieck, K. Katarzynski, M. Katsuragawa, U. Katz, D. Kerszberg, D. Khangulyan, B. Khelifi, J. King, S. Klepser, D. Klochkov, W. Kluzniak, Nu Komin, K. Kosack, S. Krakau, M. Kraus, P. P. Kruger, H. Laffon, G. Lamanna, J. Lau, J. Lefaucheur, A. Lemiere, M. Lemoine-Goumard, J-P Lenain, Eva Leser, T. Lohse, M. Lorentz, R. Liu, R. Lopez-Coto, I Lypova, D. Malyshev, V Marandon, Alexandre Marcowith, C. Mariaud, R. Marx, G. Maurin, N. Maxted, M. Mayer, P. J. Meintjes, M. Meyer, A. M. W. Mitchell, R. Moderski, M. Mohamed, L. Mohrmann, K. Mora, Emmanuel Moulin, T. Murach, S. Nakashima, M. de Naurois, H. Ndiyavala, F. Niederwanger, J. Niemiec, L. Oakes, H. Odaka, S. Ohm, M. Ostrowski, I Oya, M. Padovani, M. Panter, R. D. Parsons, N. W. Pekeur, G. Pelletier, C. Perennes, P-O Petrucci, B. Peyaud, Q. Piel, S. Pita, V Poireau, D. A. Prokhorov, H. Prokoph, G. Puehlhofer, M. Punch, A. Quirrenbach, S. Raab, R. Rauth, A. Reimer, O. Reimer, M. Renaud, R. de los Reyes, F. Rieger, L. Rinchiuso, C. Romoli, G. Rowell, B. Rudak, C. B. Rulten, V Sahakian, S. Saito, D. A. Sanchez, Andrea Santangelo, M. Sasaki, R. Schlickeiser, F. Schussler, A. Schulz, U. Schwanke, S. Schwemmer, M. Seglar-Arroyo, A. S. Seyffert, N. Shafi, I Shilon, K. Shiningayamwe, R. Simoni, H. Sol, F. Spanier, M. Spir-Jacob, L. Stawarz, R. Steenkamp, Christian Stegmann, Constantin Beverly Steppa, Iurii Sushch, T. Takahashi, J-P Tavernet, T. Tavernier, A. M. Taylor, R. Terrier, L. Tibaldo, D. Tiziani, M. Tluczykont, C. Trichard, M. Tsirou, N. Tsuji, R. Tuffs, Y. Uchiyama, D. J. van der Walt, C. van Eldik, C. van Rensburg, B. van Soelen, G. Vasileiadis, J. Veh, C. Venter, A. Viana, P. Vincent, J. Vink, F. Voisin, H. J. Voelk, T. Vuillaume, Z. Wadiasingh, S. J. Wagner, P. Wagner, R. M. Wagner, R. White, A. Wierzcholska, P. Willmann, A. Woernlein, D. Wouters, R. Yang, D. Zaborov, M. Zacharias, R. Zanin, A. A. Zdziarski, Alraune Zech, F. Zefi, A. Ziegler, J. Zorn, N. Zywucka, J. D. Magill, S. Buson, C. C. Cheung, J. S. Perkins, Y. Tanaka
- Centaurus A (Cen A) is the nearest radio galaxy discovered as a very-high-energy (VHE; 100 GeV-100 TeV) gamma-ray source by the High Energy Stereoscopic System (H.E.S.S.). It is a faint VHE gamma-ray emitter, though its VHE flux exceeds both the extrapolation from early Fermi-LAT observations as well as expectations from a (misaligned) single-zone synchrotron-self Compton (SSC) description. The latter satisfactorily reproduces the emission from Cen A at lower energies up to a few GeV. New observations with H.E.S.S., comparable in exposure time to those previously reported, were performed and eight years of Fermi-LAT data were accumulated to clarify the spectral characteristics of the gamma-ray emission from the core of Cen A. The results allow us for the first time to achieve the goal of constructing a representative, contemporaneous gamma-ray core spectrum of Cen A over almost five orders of magnitude in energy. Advanced analysis methods, including the template fitting method, allow detection in the VHE range of the core with aCentaurus A (Cen A) is the nearest radio galaxy discovered as a very-high-energy (VHE; 100 GeV-100 TeV) gamma-ray source by the High Energy Stereoscopic System (H.E.S.S.). It is a faint VHE gamma-ray emitter, though its VHE flux exceeds both the extrapolation from early Fermi-LAT observations as well as expectations from a (misaligned) single-zone synchrotron-self Compton (SSC) description. The latter satisfactorily reproduces the emission from Cen A at lower energies up to a few GeV. New observations with H.E.S.S., comparable in exposure time to those previously reported, were performed and eight years of Fermi-LAT data were accumulated to clarify the spectral characteristics of the gamma-ray emission from the core of Cen A. The results allow us for the first time to achieve the goal of constructing a representative, contemporaneous gamma-ray core spectrum of Cen A over almost five orders of magnitude in energy. Advanced analysis methods, including the template fitting method, allow detection in the VHE range of the core with a statistical significance of 12 sigma on the basis of 213 hours of total exposure time. The spectrum in the energy range of 250 GeV-6 TeV is compatible with a power-law function with a photon index Gamma = 2.52 +/- 0.13(stat) +/- 0.20(sys). An updated Fermi-LAT analysis provides evidence for spectral hardening by Delta Gamma similar or equal to 0.4 +/- 0.1 at gamma-ray energies above 2.8(-0.6)(+1.0) GeV at a level of 4.0 sigma. The fact that the spectrum hardens at GeV energies and extends into the VHE regime disfavour a single-zone SSC interpretation for the overall spectral energy distribution (SED) of the core and is suggestive of a new gamma-ray emitting component connecting the high-energy emission above the break energy to the one observed at VHE energies. The absence of significant variability at both GeV and TeV energies does not yet allow disentanglement of the physical nature of this component, though a jet-related origin is possible and a simple two-zone SED model fit is provided to this end.…
MetadatenAuthor details: | Hassan E. AbdallaORCiDGND, A. Abramowski, Felix A. AharonianORCiDGND, F. Ait Benkhali, Ekrem Oǧuzhan AngünerGND, M. Arakawa, C. Armand, M. Arrieta, M. Backes, A. Balzer, M. Barnard, Y. Becherini, J. Becker Tjus, D. Berge, S. Bernhard, K. Bernloehr, R. Blackwell, M. Bottcher, C. Boisson, J. Bolmont, S. Bonnefoy, Pol BordasORCiDGND, J. Bregeon, F. Brun, P. Brun, M. Bryan, M. Buechele, T. Bulik, M. Capasso, S. Caroff, A. Carosi, Sabrina CasanovaGND, M. Cerruti, N. Chakraborty, R. C. G. Chaves, A. Chen, J. Chevalier, S. Colafrancesco, B. Condon, J. Conrad, I. D. Davids, J. Decock, C. Deil, J. Devin, P. deWilt, L. Dirson, A. Djannati-Atai, A. Donath, J. Dyks, T. Edwards, Kathrin EgbertsGND, G. Emery, J-P Ernenwein, S. Eschbach, C. Farnier, S. Fegan, M. Fernandes, A. Fiasson, G. Fontaine, S. Funk, M. Fuessling, S. Gabici, Y. A. Gallant, T. Garrigoux, F. Gate, G. Giavitto, D. Glawion, J. F. Glicenstein, D. Gottschall, M-H Grondin, J. Hahn, M. Haupt, J. Hawkes, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, W. Hofmann, Clemens HoischenORCiDGND, T. L. Holch, M. Holler, D. Horns, A. Ivascenko, H. Iwasaki, A. Jacholkowska, M. Jamrozy, D. Jankowsky, F. Jankowsky, M. Jingo, L. Jouvin, I Jung-Richardt, M. A. Kastendieck, K. Katarzynski, M. Katsuragawa, U. Katz, D. Kerszberg, D. Khangulyan, B. Khelifi, J. King, S. Klepser, D. Klochkov, W. Kluzniak, Nu KominORCiD, K. Kosack, S. Krakau, M. Kraus, P. P. Kruger, H. Laffon, G. Lamanna, J. Lau, J. Lefaucheur, A. Lemiere, M. Lemoine-Goumard, J-P Lenain, Eva LeserORCiDGND, T. Lohse, M. Lorentz, R. Liu, R. Lopez-Coto, I Lypova, D. Malyshev, V Marandon, Alexandre MarcowithORCiD, C. Mariaud, R. Marx, G. Maurin, N. Maxted, M. Mayer, P. J. Meintjes, M. Meyer, A. M. W. Mitchell, R. Moderski, M. Mohamed, L. Mohrmann, K. Mora, Emmanuel Moulin, T. Murach, S. Nakashima, M. de Naurois, H. Ndiyavala, F. Niederwanger, J. Niemiec, L. Oakes, H. Odaka, S. Ohm, M. Ostrowski, I Oya, M. Padovani, M. Panter, R. D. Parsons, N. W. Pekeur, G. Pelletier, C. Perennes, P-O Petrucci, B. Peyaud, Q. Piel, S. Pita, V Poireau, D. A. Prokhorov, H. Prokoph, G. Puehlhofer, M. Punch, A. Quirrenbach, S. Raab, R. Rauth, A. Reimer, O. Reimer, M. Renaud, R. de los Reyes, F. Rieger, L. Rinchiuso, C. Romoli, G. Rowell, B. Rudak, C. B. Rulten, V Sahakian, S. Saito, D. A. Sanchez, Andrea Santangelo, M. Sasaki, R. Schlickeiser, F. Schussler, A. Schulz, U. Schwanke, S. Schwemmer, M. Seglar-Arroyo, A. S. Seyffert, N. Shafi, I Shilon, K. Shiningayamwe, R. Simoni, H. Sol, F. Spanier, M. Spir-Jacob, L. Stawarz, R. Steenkamp, Christian StegmannORCiDGND, Constantin Beverly SteppaORCiD, Iurii SushchORCiDGND, T. Takahashi, J-P Tavernet, T. Tavernier, A. M. Taylor, R. Terrier, L. Tibaldo, D. Tiziani, M. Tluczykont, C. Trichard, M. Tsirou, N. Tsuji, R. Tuffs, Y. Uchiyama, D. J. van der Walt, C. van Eldik, C. van Rensburg, B. van Soelen, G. Vasileiadis, J. Veh, C. Venter, A. Viana, P. Vincent, J. Vink, F. Voisin, H. J. Voelk, T. Vuillaume, Z. Wadiasingh, S. J. Wagner, P. Wagner, R. M. Wagner, R. White, A. Wierzcholska, P. Willmann, A. Woernlein, D. Wouters, R. Yang, D. Zaborov, M. Zacharias, R. Zanin, A. A. Zdziarski, Alraune ZechORCiD, F. Zefi, A. Ziegler, J. Zorn, N. Zywucka, J. D. Magill, S. Buson, C. C. Cheung, J. S. Perkins, Y. Tanaka |
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DOI: | https://doi.org/10.1051/0004-6361/201832640 |
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ISSN: | 1432-0746 |
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Title of parent work (English): | Astronomy and astrophysics : an international weekly journal |
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Publisher: | EDP Sciences |
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Place of publishing: | Les Ulis |
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Publication type: | Article |
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Language: | English |
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Date of first publication: | 2018/11/08 |
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Publication year: | 2018 |
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Creating corporation: | HESS Collaboration Fermi LAT Collaborators |
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Release date: | 2021/06/30 |
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Tag: | gamma rays: galaxies; radiation mechanisms: non-thermal |
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Volume: | 619 |
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Number of pages: | 10 |
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Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
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DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
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Peer review: | Referiert |
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Publishing method: | Open Access / Bronze Open-Access |
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