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Abdalla, Hassan E. ; Aharonian, Felix A. ; Ait Benkhali, Faical ; Angüner, Ekrem Oǧuzhan ; Arakawa, M. ; Arcaro, C. ; Armand, C. ; Arrieta, M. ; Backes, Michael ; Barnard, M. ; Becherini, Yvonne ; Tjus, J. Becker ; Berge, D. ; Bernhard, S. ; Bernlöhr, Konrad ; Blackwell, R. ; Böttcher, Markus ; Boisson, C. ; Bolmont, Julien ; Bonnefoy, S. ; Bordas, Pol ; Bregeon, J. ; Brun, F. ; Brun, P. ; Bryan, M. ; Büchele, M. ; Bulik, Tomasz ; Bylund, Tomas ; Capasso, Massimo ; Caroff, S. ; Carosi, A. ; Casanova, Sabrina ; Cerruti, Matteo ; Chakraborty, Nachiketa ; Chandra, S. ; Chaves, R. C. G. ; Chen, A. ; Colafrancesco, Sergio ; Condon, B. ; Davids, Isak ; Deil, Christoph ; Devin, J. ; deWilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Dmytriiev, A. ; Donath, Axel ; Doroshenko, Victor ; Dyks, J. ; Egberts, Kathrin ; Emery, G. ; Ernenwein, J. -P. ; Eschbach, Stefan ; Fegan, S. ; Fiasson, Armand ; Fontaine, G. ; Funk, Sebastian ; Füßling, Matthias ; Gabici, S. ; Gallant, Y. A. ; Gate, F. ; Giavitto, Gianluca ; Eisenacher Glawion, Dorit ; Glicenstein, Jean-François ; Gottschall, D. ; Grondin, Marie-Hélène ; Hahn, J. ; Haupt, M. ; Heinzelmann, G. ; Henri, Gilles ; Hermann, G. ; Hinton, James Anthony ; Hofmann, Werner ; Hoischen, Clemens ; Holch, Tim Lukas ; Holler, M. ; Horns, D. ; Huber, D. ; Iwasaki, H. ; Jacholkowska, A. ; Jamrozy, M. ; Jankowsky, David ; Jankowsky, Felix ; Jouvin, L. ; Jung-Richardt, I. ; Kastendieck, M. A. ; Katarzyński, Krzysztof ; Katsuragawa, M. ; Katz, U. ; Kerszberg, D. ; Khangulyan, D. ; Khelifi, B. ; King, J. ; Klepser, S. ; Kluzniak, W. ; Komin, Nu. ; Kosack, K. ; Krakau, S. ; Kraus, M. ; Kruger, P. P. ; Lamanna, G. ; Lau, J. ; Lefaucheur, J. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J. -P. ; Leser, Eva ; Lohse, T. ; Lorentz, M. ; Lopez-Coto, R. ; Lypova, I. ; Malyshev, D. ; Marandon, V. ; Marcowith, Alexandre ; Mariaud, C. ; Marti-Devesa, G. ; Marx, R. ; Maurin, G. ; Meintjes, P. J. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Ndiyavala, H. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Ohm, S. ; Ostrowski, M. ; Oya, I. ; Padovani, M. ; Panter, M. ; Parsons, R. D. ; Perennes, C. ; Petrucci, P. -O. ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poireau, V. ; Noel, A. Priyana ; Prokhorov, D. A. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Rauth, R. ; Reimer, A. ; Reimer, O. ; Renaud, M. ; Rieger, F. ; Rinchiuso, L. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Ruiz-Velasco, E. ; Sahakian, V. ; Saito, S. ; Sanchez, D. A. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schussler, F. ; Schulz, A. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Senniappan, M. ; Seyffert, A. S. ; Shafi, N. ; Shilon, I. ; Shiningayamwe, K. ; Simoni, R. ; Sinha, A. ; Sol, H. ; Spanier, F. ; Specovius, A. ; Spir-Jacob, M. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Steppa, Constantin Beverly ; Takahashi, T. ; Tavernet, J. -P. ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tibaldo, L. ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsirou, M. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venter, C. ; Viana, A. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; Wagner, R. M. ; White, R. ; Wierzcholska, A. ; Yang, R. ; Zaborov, D. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. ; Zech, Alraune ; Zefi, F. ; Ziegler, A. ; Zorn, J. ; Zywucka, N. ; Cirelli, M. ; Panci, P. ; Sala, F. ; Silk, J. ; Taoso, M.
Dwarf spheroidal galaxies are among the most promising targets for detecting signals of Dark Matter (DM) annihilations. The H.E.S.S. experiment has observed five of these systems for a total of about 130 hours. The data are re-analyzed here, and, in the absence of any detected signals, are interpreted in terms of limits on the DM annihilation cross section. Two scenarios are considered: i) DM annihilation into mono-energetic gamma-rays and ii) DM in the form of pure WIMP multiplets that, annihilating into all electroweak bosons, produce a distinctive gamma-ray spectral shape with a high-energy peak at the DM mass and a lower-energy continuum. For case i), upper limits at 95% confidence level of about <sigma upsilon > less than or similar to 3 x 10(-25) cm(3) s(-1) are obtained in the mass range of 400 GeV to 1TeV. For case ii), the full spectral shape of the models is used and several excluded regions are identified, but the thermal masses of the candidates are not robustly ruled out.
Abdalla, Hassan E. ; Aharonian, Felix A. ; Benkhali, F. Ait ; Anguener, E. O. ; Arakawa, M. ; Arcaro, C. ; Armand, C. ; Ashkar, H. ; Backes, M. ; Martins, V. Barbosa ; Barnard, M. ; Becherini, Y. ; Berge, D. ; Bernloehr, K. ; Blackwell, R. ; Boettcher, M. ; Boisson, C. ; Bolmont, J. ; Bonnefoy, S. ; Bregeon, J. ; Breuhaus, M. ; Brun, F. ; Brun, P. ; Bryan, M. ; Buechele, M. ; Bulik, T. ; Bylund, T. ; Capasso, M. ; Caroff, S. ; Carosi, A. ; Casanova, Sabrina ; Cerruti, M. ; Chakraborty, N. ; Chand, T. ; Chandra, S. ; Chaves, R. C. G. ; Chen, A. ; Colafrancesco, S. ; Curylo, M. ; Davids, I. D. ; Deil, C. ; Devin, J. ; de Wilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Dmytriiev, A. ; Donath, A. ; Doroshenko, V ; Dyks, J. ; Egberts, Kathrin ; Emery, G. ; Ernenwein, J-p ; Eschbach, S. ; Feijen, K. ; Fegan, S. ; Fiasson, A. ; Fontaine, G. ; Funk, S. ; Fuessling, M. ; Gabici, S. ; Gallant, Y. A. ; Gate, F. ; Giavitto, G. ; Glawion, D. ; Glicenstein, J. F. ; Gottschall, D. ; Grondin, M-H ; Hahn, J. ; Haupt, M. ; Heinzelmann, G. ; Henri, G. ; Hermann, G. ; Hinton, James Anthony ; Hofmann, W. ; Hoischen, Clemens ; Holch, Tim Lukas ; Holler, M. ; Horns, D. ; Huber, D. ; Iwasaki, H. ; Jamrozy, M. ; Jankowsky, D. ; Jankowsky, F. ; Jung-Richardt, I ; Kastendieck, M. A. ; Katarzynski, K. ; Katsuragawa, M. ; Katz, U. ; Khangulyan, D. ; Khelifi, B. ; King, J. ; Klepser, S. ; Kluzniak, W. ; Komin, Nu ; Kosack, K. ; Kostunin, D. ; Kraus, M. ; Lamanna, G. ; Lau, J. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J-P ; Leser, Eva ; Levy, C. ; Lohse, T. ; Lopez-Coto, R. ; Lypova, I ; Mackey, J. ; Majumdar, J. ; Malyshev, D. ; Marandon, V ; Marcowith, Alexandre ; Mares, A. ; Mariaud, C. ; Marti-Devesa, G. ; Marx, R. ; Maurin, G. ; Meintjes, P. J. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Muller, J. ; Moore, C. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Ndiyavala, H. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Ohm, S. ; Wilhelmi, E. de Ona ; Ostrowski, M. ; Oya, I ; Panter, M. ; Parsons, R. D. ; Perennes, C. ; Petrucci, P-O ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poireau, V ; Noel, A. Priyana ; Prokhorov, D. A. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Rauth, R. ; Reimer, A. ; Reimer, O. ; Remy, Q. ; Renaud, M. ; Rieger, F. ; Rinchiuso, L. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Ruiz-Velasco, E. ; Sahakian, V ; Saito, S. ; Sanchez, David M. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schussler, F. ; Schulz, A. ; Schutte, H. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Senniappan, M. ; Seyffert, A. S. ; Shafi, N. ; Shiningayamwe, K. ; Simoni, R. ; Sinha, A. ; Sol, H. ; Specovius, A. ; Spir-Jacob, M. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Steppa, Constantin Beverly ; Takahashi, T. ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsirou, M. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venter, C. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; White, R. ; Wierzcholska, A. ; Yang, R. ; Yoneda, H. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. A. ; Zech, Alraune ; Ziegler, A. ; Zorn, J. ; Zywucka, N. ; Maxted, N.
Young core-collapse supernovae with dense-wind progenitors may be able to accelerate cosmic-ray hadrons beyond the knee of the cosmic-ray spectrum, and this may result in measurable gamma-ray emission. We searched for gamma-ray emission from ten super- novae observed with the High Energy Stereoscopic System (H.E.S.S.) within a year of the supernova event. Nine supernovae were observed serendipitously in the H.E.S.S. data collected between December 2003 and December 2014, with exposure times ranging from 1.4 to 53 h. In addition we observed SN 2016adj as a target of opportunity in February 2016 for 13 h. No significant gamma-ray emission has been detected for any of the objects, and upper limits on the >1 TeV gamma-ray flux of the order of similar to 10(-13) cm(-)(2)s(-1) are established, corresponding to upper limits on the luminosities in the range similar to 2 x 10(39) to similar to 1 x 10(42) erg s(-1). These values are used to place model-dependent constraints on the mass-loss rates of the progenitor stars, implying upper limits between similar to 2 x 10(-5) and similar to 2 x 10(-3) M-circle dot yr(-1) under reasonable assumptions on the particle acceleration parameters.
Abdalla, Hassan E. ; Abramowski, A. ; Aharonian, Felix A. ; Benkhali, F. Ait ; Akhperjanian, A. G. ; Andersson, T. ; Anguener, E. O. ; Arakawa, M. ; Arrieta, M. ; Aubert, P. ; Backes, M. ; Balzer, A. ; Barnard, M. ; Becherini, Y. ; Tjus, J. Becker ; Berge, D. ; Bernhard, S. ; Bernloehr, K. ; Blackwell, R. ; Boettcher, M. ; Boisson, C. ; Bolmont, J. ; Bonnefoy, S. ; Bordas, Pol ; Bregeon, J. ; Brun, F. ; Brun, P. ; Bryan, M. ; Buechele, M. ; Bulik, T. ; Capasso, M. ; Carr, J. ; Casanova, Sabrina ; Cerruti, M. ; Chakraborty, N. ; Chaves, R. C. G. ; Chen, A. ; Chevalier, J. ; Coffaro, M. ; Colafrancesco, S. ; Cologna, G. ; Condon, B. ; Conrad, J. ; Cui, Y. ; Davids, I. D. ; Decock, J. ; Degrange, B. ; Deil, C. ; Devin, J. ; deWilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Domainko, W. ; Donath, A. ; Dutson, K. ; Dyks, J. ; Edwards, T. ; Egberts, Kathrin ; Eger, P. ; Ernenwein, J. -P. ; Eschbach, S. ; Farnier, C. ; Fegan, S. ; Fernandes, M. V. ; Fiasson, A. ; Fontaine, G. ; Foerster, A. ; Funk, S. ; Fuessling, M. ; Gabici, S. ; Gallant, Y. A. ; Garrigoux, T. ; Giavitto, G. ; Giebels, B. ; Glicenstein, J. F. ; Gottschall, D. ; Goyal, A. ; Grondin, M. -H. ; Hahn, J. ; Haupt, M. ; Hawkes, J. ; Heinzelmann, G. ; Henri, G. ; Hermann, G. ; Hinton, J. A. ; Hofmann, W. ; Hoischen, Clemens ; Holch, T. L. ; Holler, M. ; Horns, D. ; Ivascenko, A. ; Iwasaki, H. ; Jacholkowska, A. ; Jamrozy, M. ; Janiak, M. ; Jankowsky, D. ; Jankowsky, F. ; Jingo, M. ; Jogler, T. ; Jouvin, L. ; Jung-Richardt, I. ; Kastendieck, M. A. ; Katarzynski, K. ; Katsuragawa, M. ; Katz, U. ; Kerszberg, D. ; Khangulyan, D. ; Khelifi, B. ; King, J. ; Klepser, S. ; Klochkov, D. ; Kluzniak, W. ; Kolitzus, D. ; Komin, Nu. ; Kosack, K. ; Krakau, S. ; Kraus, M. ; Krueger, P. P. ; Laffon, H. ; Lamanna, G. ; Lau, J. ; Lees, J. -P. ; Lefaucheur, J. ; Lefranc, V. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J. -P. ; Leser, Eva ; Lohse, T. ; Lorentz, M. ; Liu, R. ; Lopez-Coto, R. ; Lypova, I. ; Marandon, V. ; Marcowith, Alexandre ; Mariaud, C. ; Marx, R. ; Maurin, G. ; Maxted, N. ; Mayer, M. ; Meintjes, P. J. ; Meyer, M. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Mora, K. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Ohm, S. ; Ostrowski, M. ; Oya, I. ; Padovani, M. ; Panter, M. ; Parsons, R. D. ; Pekeur, N. W. ; Pelletier, G. ; Perennes, C. ; Petrucci, P. -O. ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poon, H. ; Prokhorov, D. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Rauth, R. ; Reimer, A. ; Reimer, O. ; Renaud, M. ; de los Reyes, R. ; Richter, S. ; Rieger, F. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Rulten, C. B. ; Sahakian, V. ; Saito, S. ; Salek, D. ; Sanchez, D. A. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schuessler, F. ; Schulz, A. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Settimo, M. ; Seyffert, A. S. ; Shafi, N. ; Shilon, I. ; Simoni, R. ; Sol, H. ; Spanier, F. ; Spengler, G. ; Spies, F. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Stycz, K. ; Sushch, I. ; Takahashi, T. ; Tavernet, J. -P. ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tibaldo, L. ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venters, C. ; Viana, A. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; Wagner, P. ; Wagner, R. M. ; White, R. ; Wierzcholska, A. ; Willmann, P. ; Woernlein, A. ; Wouters, D. ; Yang, R. ; Zaborov, D. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. A. ; Zech, Alraune ; Zefi, F. ; Ziegler, A. ; Zywucka, N.
The diffuse very high-energy (VHE; > 100 GeV) gamma-ray emission observed in the central 200 pc of the Milky Way by H.E.S.S. was found to follow dense matter distribution in the central molecular zone (CMZ) up to a longitudinal distance of about 130 pc to the Galactic centre (GC), where the flux rapidly decreases. This was initially interpreted as the result of a burst-like injection of energetic particles 104 yr ago, but a recent more sensitive H.E.S.S. analysis revealed that the cosmic-ray (CR) density profile drops with the distance to the centre, making data compatible with a steady cosmic PeVatron at the GC. In this paper, we extend this analysis to obtain, for the first time, a detailed characterisation of the correlation with matter and to search for additional features and individual gamma-ray sources in the inner 200 pc. Taking advantage of 250 h of H.E.S.S. data and improved analysis techniques, we perform a detailed morphology study of the diffuse VHE emission observed from the GC ridge and reconstruct its total spectrum. To test the various contributions to the total gamma-ray emission, we used an iterative 2D maximum-likelihood approach that allows us to build a phenomenological model of the emission by summing a number of different spatial components. We show that the emission correlated with dense matter covers the full CMZ and that its flux is about half the total diffuse emission flux. We also detect some emission at higher latitude that is likely produced by hadronic collisions of CRs in less dense regions of the GC interstellar medium. We detect an additional emission component centred on the GC and extending over about 15 pc that is consistent with the existence of a strong CR density gradient and confirms the presence of a CR accelerator at the very centre of our Galaxy. We show that the spectrum of full ridge diffuse emission is compatible with that previously derived from the central regions, suggesting that a single population of particles fills the entire CMZ. Finally, we report the discovery of a VHE gamma-ray source near the GC radio arc and argue that it is produced by the pulsar wind nebula candidate G0.13-0.11.
Abdalla, Hassan E. ; Abramowski, A. ; Aharonian, Felix A. ; Benkhali, F. Ait ; Akhperjanian, A. G. ; Andersson, T. ; Anguener, E. O. ; Arakawa, M. ; Arrieta, M. ; Aubert, P. ; Backes, M. ; Balzer, A. ; Barnard, M. ; Becherini, Y. ; Tjus, J. Becker ; Berge, D. ; Bernhard, S. ; Bernloehr, K. ; Blackwell, R. ; Bottcher, M. ; Boisson, C. ; Bolmont, J. ; Bordas, Pol ; Bregeon, J. ; Brun, F. ; Brun, P. ; Bryan, M. ; Buechele, M. ; Bulik, T. ; Capasso, M. ; Carr, J. ; Casanova, Sabrina ; Cerruti, M. ; Chakraborty, N. ; Chalme-Calvet, R. ; Chaves, R. C. G. ; Chen, A. ; Chevalier, J. ; Chretien, M. ; Coffaro, M. ; Colafrancesco, S. ; Cologna, G. ; Condon, B. ; Conrad, J. ; Cui, Y. ; Davids, I. D. ; Decock, J. ; Degrange, B. ; Deil, C. ; Devin, J. ; deWilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Domainko, W. ; Donath, A. ; Dutson, K. ; Dyks, J. ; Edwards, T. ; Egberts, Kathrin ; Eger, P. ; Ernenwein, J. -P. ; Eschbach, S. ; Farnier, C. ; Fegan, S. ; Fernandes, M. V. ; Fiasson, A. ; Fontaine, G. ; Foerster, A. ; Funk, S. ; Fuessling, M. ; Gabici, S. ; Gajdus, M. ; Gallant, Y. A. ; Garrigoux, T. ; Giavitto, G. ; Giebels, B. ; Glicenstein, J. F. ; Gottschall, D. ; Goyal, A. ; Grondin, M. -H. ; Hahn, J. ; Haupt, M. ; Hawkes, J. ; Heinzelmann, G. ; Henri, G. ; Hermann, G. ; Hervet, O. ; Hinton, J. A. ; Hofmann, W. ; Hoischen, Clemens ; Holler, M. ; Horns, D. ; Ivascenko, A. ; Iwasaki, H. ; Jacholkowska, A. ; Jamrozy, M. ; Janiak, M. ; Jankowsky, D. ; Jankowsky, F. ; Jingo, M. ; Jogler, T. ; Jouvin, L. ; Jung-Richardt, I. ; Kastendieck, M. A. ; Katarzynski, K. ; Katsuragawa, M. ; Katz, U. ; Kerszberg, D. ; Khangulyan, D. ; Khelifi, B. ; Kieffer, M. ; King, J. ; Klepser, S. ; Klochkov, D. ; Kluzniak, W. ; Kolitzus, D. ; Komin, Nu. ; Kosack, K. ; Krakau, S. ; Kraus, M. ; Kruger, P. P. ; Laffon, H. ; Lamanna, G. ; Lau, J. ; Lees, J. -P. ; Lefaucheur, J. ; Lefranc, V. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J. -P. ; Leser, Eva ; Lohse, T. ; Lorentz, M. ; Liu, R. ; Lopez-Coto, R. ; Lypova, I. ; Marandon, V. ; Marcowith, Alexandre ; Mariaud, C. ; Marx, R. ; Maurin, G. ; Maxted, N. ; Mayer, M. ; Meintjes, P. J. ; Meyer, M. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Mora, K. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Oettl, S. ; Ohm, S. ; Ostrowski, M. ; Oya, I. ; Padovani, M. ; Panter, M. ; Parsons, R. D. ; Pekeur, N. W. ; Pelletier, G. ; Perennes, C. ; Petrucci, P. -O. ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poon, H. ; Prokhorov, D. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Reimer, A. ; Reimer, O. ; Renaud, M. ; de los Reyes, R. ; Richter, S. ; Rieger, F. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Rulten, C. B. ; Sahakian, V. ; Saito, S. ; Salek, D. ; Sanchez, D. A. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schussler, F. ; Schulz, A. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Settimo, M. ; Seyffert, A. S. ; Shafi, N. ; Shilon, I. ; Simoni, R. ; Sol, H. ; Spanier, F. ; Spengler, G. ; Spies, F. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian Michael ; Stycz, K. ; Sushch, I. ; Takahashi, T. ; Tavernet, J. -P. ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tibaldo, L. ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venter, C. ; Viana, A. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; Wagner, P. ; Wagner, R. M. ; White, R. ; Wierzcholska, A. ; Willmann, P. ; Woernlein, A. ; Wouters, D. ; Yang, R. ; Zabalza, V. ; Zaborov, D. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. A. ; Zech, Alraune ; Zefi, F. ; Ziegler, A. ; Zywucka, N.
Context. Runaway stars form bow shocks by ploughing through the interstellar medium at supersonic speeds and are promising sources of non-thermal emission of photons. One of these objects has been found to emit non-thermal radiation in the radio band. This triggered the development of theoretical models predicting non-thermal photons from radio up to very-high-energy (VHE, E >= 0.1 TeV) gamma rays. Subsequently, one bow shock was also detected in X-ray observations. However, the data did not allow discrimination between a hot thermal and a non-thermal origin. Further observations of different candidates at X-ray energies showed no evidence for emission at the position of the bow shocks either. A systematic search in the Fermi-LAT energy regime resulted in flux upper limits for 27 candidates listed in the E-BOSS catalogue. Aims. Here we perform the first systematic search for VHE gamma-ray emission from bow shocks of runaway stars. Methods. Using all available archival H.E.S.S. data we search for very-high-energy gamma-ray emission at the positions of bow shock candidates listed in the second E-BOSS catalogue release. Out of the 73 bow shock candidates in this catalogue, 32 have been observed with H.E.S.S. Results. None of the observed 32 bow shock candidates in this population study show significant emission in the H.E.S.S. energy range. Therefore, flux upper limits are calculated in five energy bins and the fraction of the kinetic wind power that is converted into VHE gamma rays is constrained. Conclusions. Emission from stellar bow shocks is not detected in the energy range between 0.14 and 18 TeV. The resulting upper limits constrain the level of VHE gamma-ray emission from these objects down to 0.1-1% of the kinetic wind energy.
Abdalla, Hassan E. ; Aharonian, Felix A. ; Benkhali, F. Ait ; Angüner, Ekrem Oǧuzhan ; Arakawa, M. ; Arcaro, C. ; Armand, C. ; Backes, M. ; Barnard, M. ; Becherini, Y. ; Berge, D. ; Bernloehr, K. ; Blackwell, R. ; Bottcher, M. ; Boisson, C. ; Bolmont, J. ; Bonnefoy, S. ; Bregeon, J. ; Brun, F. ; Brun, P. ; Bryan, M. ; Buechele, M. ; Bulik, T. ; Bylund, T. ; Capasso, M. ; Caroff, S. ; Carosi, A. ; Casanova, Sabrina ; Cerruti, M. ; Chakraborty, N. ; Chand, T. ; Chandra, S. ; Chaves, R. C. G. ; Chen, A. ; Colafrancesco, S. ; Condon, B. ; Davids, I. D. ; Deil, C. ; Devin, J. ; deWilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Dmytriiev, A. ; Donath, A. ; Doroshenko, V ; Dyks, J. ; Egberts, Kathrin ; Emery, G. ; Ernenwein, J-P ; Eschbach, S. ; Feijen, K. ; Fegan, S. ; Fiasson, A. ; Fontaine, G. ; Funk, S. ; Fuessling, M. ; Gabici, S. ; Gallant, Y. A. ; Gate, F. ; Giavitto, G. ; Glawion, D. ; Glicenstein, J. F. ; Gottschall, D. ; Grondin, M-H ; Hahn, J. ; Haupt, M. ; Heinzelmann, G. ; Henri, G. ; Hermann, G. ; Hinton, James Anthony ; Hofmann, W. ; Hoischen, Clemens ; Holch, Tim Lukas ; Holler, M. ; Horns, D. ; Huber, D. ; Iwasaki, H. ; Jacholkowska, A. ; Jamrozy, M. ; Jankowsky, D. ; Jankowsky, F. ; Jouvin, L. ; Jung-Richardt, I ; Kastendieck, M. A. ; Katarzynski, K. ; Katsuragawa, M. ; Katz, U. ; Khangulyan, D. ; Khelifi, B. ; King, J. ; Klepser, S. ; Kluzniak, W. ; Komin, Nu ; Kosack, K. ; Kostunin, D. ; Kraus, M. ; Lamanna, G. ; Lau, J. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J-P ; Leser, Eva ; Lohse, T. ; Lopez-Coto, R. ; Lypova, I ; Malyshev, D. ; Marandon, V ; Marcowith, Alexandre ; Mariaud, C. ; Marti-Devesa, G. ; Marx, R. ; Maurin, G. ; Maxted, N. ; Meintjes, P. J. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Moore, C. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Ndiyavala, H. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Ohm, S. ; Wilhelmi, E. de Ona ; Ostrowski, M. ; Oya, I ; Panter, M. ; Parsons, R. D. ; Perennes, C. ; Petrucci, P-O ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poireau, V ; Noel, A. Priyana ; Prokhorov, D. A. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Rauth, R. ; Reimer, A. ; Reimer, O. ; Renaud, M. ; Rieger, F. ; Rinchiuso, L. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Ruiz-Velasco, E. ; Sahakian, V ; Saito, S. ; Sanchez, David M. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schussler, F. ; Schulz, A. ; Schutte, H. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Senniappan, M. ; Seyffert, A. S. ; Shafi, N. ; Shilon, I ; Shiningayamwe, K. ; Simoni, R. ; Sinha, A. ; Sol, H. ; Specovius, A. ; Spir-Jacob, M. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Steppa, Constantin Beverly ; Takahashi, T. ; Tavernet, J-P ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tibaldo, Luigi ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsirou, M. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venter, C. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; White, R. ; Wierzcholska, A. ; Yang, R. ; Yoneda, H. ; Zaborov, D. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. A. ; Zech, Alraune ; Ziegler, A. ; Zorn, J. ; Zywucka, N.
Context. Pulsar wind nebulae (PWNe) represent the most prominent population of Galactic very-high-energy gamma-ray sources and are thought to be an efficient source of leptonic cosmic rays. Vela X is a nearby middle-aged PWN, which shows bright X-ray and TeV gamma-ray emission towards an elongated structure called the cocoon. Aims. Since TeV emission is likely inverse-Compton emission of electrons, predominantly from interactions with the cosmic microwave background, while X-ray emission is synchrotron radiation of the same electrons, we aim to derive the properties of the relativistic particles and of magnetic fields with minimal modelling. Methods. We used data from the Suzaku XIS to derive the spectra from three compact regions in Vela X covering distances from 0.3 to 4 pc from the pulsar along the cocoon. We obtained gamma-ray spectra of the same regions from H.E.S.S. observations and fitted a radiative model to the multi-wavelength spectra. Results. The TeV electron spectra and magnetic field strengths are consistent within the uncertainties for the three regions, with energy densities of the order 10(-12) erg cm(-3). The data indicate the presence of a cutoff in the electron spectrum at energies of similar to 100 TeV and a magnetic field strength of similar to 6 mu G. Constraints on the presence of turbulent magnetic fields are weak. Conclusions. The pressure of TeV electrons and magnetic fields in the cocoon is dynamically negligible, requiring the presence of another dominant pressure component to balance the pulsar wind at the termination shock. Sub-TeV electrons cannot completely account for the missing pressure, which may be provided either by relativistic ions or from mixing of the ejecta with the pulsar wind. The electron spectra are consistent with expectations from transport scenarios dominated either by advection via the reverse shock or by diffusion, but for the latter the role of radiative losses near the termination shock needs to be further investigated in the light of the measured cutoff energies. Constraints on turbulent magnetic fields and the shape of the electron cutoff can be improved by spectral measurements in the energy range greater than or similar to 10 keV.
Abdalla, Hassan E. ; Collaboration, H. E. S. S. ; Abramowski, A. ; Aharonian, Felix A. ; Benkhali, F. Ait ; Angüner, Ekrem Oǧuzhan ; Arakawa, M. ; Armand, C. ; Arrieta, M. ; Backes, M. ; Balzer, A. ; Barnard, M. ; Becherini, Y. ; Tjus, J. Becker ; Berge, D. ; Bernhard, S. ; Bernloehr, K. ; Blackwell, R. ; Bottcher, M. ; Boisson, C. ; Bolmont, J. ; Bonnefoy, S. ; Bordas, Pol ; Bregeon, J. ; Brun, F. ; Brun, P. ; Bryan, M. ; Buechele, M. ; Bulik, T. ; Capasso, M. ; Caroff, S. ; Carosi, A. ; Casanova, Sabrina ; Cerruti, M. ; Chakraborty, N. ; Chaves, R. C. G. ; Chen, A. ; Chevalier, J. ; Colafrancesco, S. ; Condon, B. ; Conrad, J. ; Davids, I. D. ; Decock, J. ; Deil, C. ; Devin, J. ; deWilt, P. ; Dirson, L. ; Djannati-Atai, A. ; Donath, A. ; Dyks, J. ; Edwards, T. ; Egberts, Kathrin ; Emery, G. ; Ernenwein, J. -P. ; Eschbach, S. ; Farnier, C. ; Fegan, S. ; Fernandes, M. V. ; Fiasson, A. ; Fontaine, G. ; Funk, S. ; Fuessling, M. ; Gabici, S. ; Gallant, Y. A. ; Garrigoux, T. ; Gate, F. ; Giavitto, G. ; Glawion, D. ; Glicenstein, J. F. ; Gottschall, D. ; Grondin, M. -H. ; Hahn, J. ; Haupt, M. ; Hawkes, J. ; Heinzelmann, G. ; Henri, G. ; Hermann, G. ; Hinton, J. A. ; Hofmann, W. ; Hoischen, Clemens ; Holch, T. L. ; Holler, M. ; Horns, D. ; Ivascenko, A. ; Iwasaki, H. ; Jacholkowska, A. ; Jamrozy, M. ; Jankowsky, D. ; Jankowsky, F. ; Jingo, M. ; Jouvin, L. ; Jung-Richardt, I. ; Kastendieck, M. A. ; Katarzynski, K. ; Katsuragawa, M. ; Katz, U. ; Kerszberg, D. ; Khangulyan, D. ; Khelifi, B. ; King, J. ; Klepser, S. ; Klochkov, D. ; Kluzniak, W. ; Komin, Nu. ; Kosack, K. ; Krakau, S. ; Kraus, M. ; Kruger, P. P. ; Laffon, H. ; Lamanna, G. ; Lau, J. ; Lefaucheur, J. ; Lemiere, A. ; Lemoine-Goumard, M. ; Lenain, J. -P. ; Leser, Eva ; Lohse, T. ; Lorentz, M. ; Liu, R. ; Lopez-Coto, R. ; Lypova, I. ; Malyshev, D. ; Marandon, V. ; Marcowith, Alexandre ; Mariaud, C. ; Marx, R. ; Maurin, G. ; Maxted, N. ; Mayer, M. ; Meintjes, P. J. ; Meyer, M. ; Mitchell, A. M. W. ; Moderski, R. ; Mohamed, M. ; Mohrmann, L. ; Mora, K. ; Moulin, Emmanuel ; Murach, T. ; Nakashima, S. ; de Naurois, M. ; Ndiyavala, H. ; Niederwanger, F. ; Niemiec, J. ; Oakes, L. ; Odaka, H. ; Ohm, S. ; Ostrowski, M. ; Oya, I. ; Padovani, M. ; Panter, M. ; Parsons, R. D. ; Pekeur, N. W. ; Pelletier, G. ; Perennes, C. ; Petrucci, P. -O. ; Peyaud, B. ; Piel, Q. ; Pita, S. ; Poireau, V. ; Prokhorov, D. A. ; Prokoph, H. ; Puehlhofer, G. ; Punch, M. ; Quirrenbach, A. ; Raab, S. ; Rauth, R. ; Reimer, A. ; Reimer, O. ; Renaud, M. ; de los Reyes, R. ; Rieger, F. ; Rinchiuso, L. ; Romoli, C. ; Rowell, G. ; Rudak, B. ; Rulten, C. B. ; Sahakian, V. ; Saito, S. ; Sanchez, D. A. ; Santangelo, A. ; Sasaki, M. ; Schlickeiser, R. ; Schussler, F. ; Schulz, A. ; Schwanke, U. ; Schwemmer, S. ; Seglar-Arroyo, M. ; Seyffert, A. S. ; Shafi, N. ; Shilon, I. ; Shiningayamwe, K. ; Simoni, R. ; Sol, H. ; Spanier, F. ; Spir-Jacob, M. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Steppa, Constantin Beverly ; Sushch, I. ; Takahashi, T. ; Tavernet, J. -P. ; Tavernier, T. ; Taylor, A. M. ; Terrier, R. ; Tibaldo, L. ; Tiziani, D. ; Tluczykont, M. ; Trichard, C. ; Tsirou, M. ; Tsuji, N. ; Tuffs, R. ; Uchiyama, Y. ; van der Walt, D. J. ; van Eldik, C. ; van Rensburg, C. ; van Soelen, B. ; Vasileiadis, G. ; Veh, J. ; Venter, C. ; Viana, A. ; Vincent, P. ; Vink, J. ; Voisin, F. ; Voelk, H. J. ; Vuillaume, T. ; Wadiasingh, Z. ; Wagner, S. J. ; Wagner, P. ; Wagner, R. M. ; White, R. ; Wierzcholska, A. ; Willmann, P. ; Woernlein, A. ; Wouters, D. ; Yang, R. ; Zaborov, D. ; Zacharias, M. ; Zanin, R. ; Zdziarski, A. A. ; Zech, Alraune ; Zefi, F. ; Ziegler, A. ; Zorn, J. ; Zywucka, N.
Context. Recently, the high-energy (HE, 0.1-100 GeV) gamma-ray emission from the object LMC P3 in the Large Magellanic Cloud (LMC) has been discovered to be modulated with a 10.3-day period, making it the first extra-galactic gamma-ray binary. Aims. This work aims at the detection of very-high-energy (VHE, >100 GeV) gamma-ray emission and the search for modulation of the VHE signal with the orbital period of the binary system. Methods. LMC P3 has been observed with the High Energy Stereoscopic System (H.E.S.S.); the acceptance-corrected exposure time is 100 h. The data set has been folded with the known orbital period of the system in order to test for variability of the emission. Results. VHE gamma-ray emission is detected with a statistical significance of 6.4 sigma. The data clearly show variability which is phase-locked to the orbital period of the system. Periodicity cannot be deduced from the H.E.S.S. data set alone. The orbit-averaged luminosity in the 1-10 TeV energy range is (1.4 +/- 0.2) x 10(35) erg s(-1). A luminosity of (5 +/- 1) x 10(35) erg s(-1) is reached during 20% of the orbit. HE and VHE gamma-ray emissions are anti-correlated. LMC P3 is the most luminous gamma-ray binary known so far.