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1. Very high energy γ-ray observations of the binary PSR B1259–63/SS2883 around the 2007 Periastron

Author: A. A. Zdziarski, M. K. Daniel, Gavin Rowell, L. Venter, A. C. Clapson, M. C. Medina, T. J. L. McComb, Gilles Henri, Marek Sikora, W. Domainko, P. H. Tam, S. Rosier-Lees, P. Espigat, S. Schwemmer, Cameron B Rulten, Andrea Santangelo, Michal Dyrda, K. Katarzyński, M. Kerschhaggl, Michael Punch, Felix Aharonian, Guillaume Dubus, Jacek Niemiec, B. C. Raubenheimer, B. Giebels, A. R. Bazer-Bachi, F. Brun, O. Tibolla, A. Shalchi, D. Gerbig, M. Panter, J. L. Skilton, O. C. de Jager, S. Schwarzburg, D. Nedbal, M. Vivier, Karl Kosack, Christian Farnier, C. Stegmann, I. Jung, Stefan Wagner, Gisela Anton, Dieter Horns, Pierre Brun, Łukasz Stawarz, B. Rudak, Kathrin Egberts, G. Lamanna, B. Degrange, A. Cheesebrough, J. Dyks, Heinrich J. Völk, P. Vincent, I. D. Davids, Frank M. Rieger, D. Göring, David Maurin, S. Pita, V. Borrel, M. Tluczykont, Y. A. Gallant, Stefan Ohm, G. Coignet, J-F. Olive, Martin Ward, B. Behera, L. Rob, V. Sahakian, G. Vasileiadis, Rolf Bühler, Andreas Quirrenbach, J.-P. Tavernet, A. Hoffmann, J. F. Glicenstein, R. Kossakowski, F. M. Schöck, M. Paz Arribas, G. Heinzelmann, J. Bolmont, Ullrich Schwanke, M. Dalton, A. G. Akhperjanian, R. Steenkamp, G. Pedaletti, J.-P. Lenain, P. M. Chadwick, Francesca Volpe, B. Nicholas, Anna Szostek, F. Dubois, Konrad Bernlöhr, G. Superina, G. Pühlhofer, A. Fiasson, Timothé Boutelier, Emmanuel Moulin, Reinhard Schlickeiser, Hugh Dickinson, V. Marandon, Christo Venter, C. Jahn, U. F. Katz, A. Zech, A. Djannati-Ataï, M. Hauser, C. van Eldik, M. Holleran, M. Renaud, D. Hauser, D. Klochkov, Catherine Boisson, Rafal Moderski, Dimitrios Emmanoulopoulos, H. Sol, R. C. G. Chaves, S. M. Rayner, J. P. Vialle, P. Goret, Guy Pelletier, A. Förster, Martin Raue, S. Hoppe, A. Charbonnier, S. Heinz, L. O'c. Drury, M. Füßling, E. de Oña Wilhelmi, Sarah Kaufmann, L. Gérard, B. Glück, Nu. Komin, T. Bulik, Christoph Deil, T. Kneiske, I. Büsching, P.-O. Petrucci, L.-M. Chounet, Yvonne Becherini, D. Nekrassov, W. Kluźniak, A. Jacholkowska, G. Fontaine, S. J. Nolan, Jim Hinton, Dmitry Khangulyan, Thomas Lohse, Michał Ostrowski, K. J. Orford, J. Ripken, D. Keogh, Werner Hofmann, U. Barres de Almeida, F. Feinstein, Julien Masbou, Stefano Gabici, M. de Naurois, Alexandre Marcowith, O. Martineau-Huynh, B. Khélifi, G. Hermann, Regis Terrier, J. Ruppel, J. Brucker, D. Spangler, M. Naumann-Godo, F. Stinzing, A. Bochow, Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), APC - Astrophysique des Hautes Energies (APC - AHE), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESS, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, and Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], observational [methods], Flux, Astrophysics, 01 natural sciences, Spectral line, neutron [stars], Pulsar, 0103 physical sciences, Binary star, 010303 astronomy & astrophysics, Astroparticle physics, Physics, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], binaries: general [stars], Gamma ray, observations [gamma rays], Astronomy, telescopes, Astronomy and Astrophysics, non-thermal [radiation mechanisms], Light curve, Neutron star, 13. Climate action, Space and Planetary Science
Abstract: Aims. This article presents very-high-energy (VHE; E > 100 GeV) data from the $\gamma$-ray binary PSR B1259-63 as taken during the years 2005, 2006 and before as well as shortly after the 2007 periastron passage. These data extend the knowledge of the lightcurve of this object to all phases of the 3.4 year binary orbit. The lightcurve constrains physical mechanisms present in this TeV source. Methods. Observations of VHE $\gamma$-rays with the HESS telescope array using the Imaging Atmospheric Cherenkov Technique were performed. The HESS instrument features an angular resolution of < 0.1° and an energy resolution of < 20%. Gamma-ray events in an energy range of 0.5-70 TeV were recorded. From these data, energy spectra and lightcurve with a monthly time sampling were extracted. Results. VHE $\gamma$-ray emission from PSR B1259-63 was detected with an overall significance of 9.5 standard deviations using 55h of exposure, obtained from April to August 2007. The monthly flux of $\gamma$-rays during the observation period was measured, yielding VHE lightcurve data for the early pre-periastron phase of the system for the first time. No spectral variability was found on timescales of months. The spectrum is described by a power law with a photon index of $\Gamma$ = 2.8 $\pm$ 0.2stat $\pm$ 0.2sys and flux normalisation $\Phi_{0}$ = (1.1 $\pm$ 0.1stat $\pm$ 0.2sys) $\times$ 10-12 TeV-1 cm-2 s-1. PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of $\gamma$-rays is seen in those observations. Conclusions. PSR B1259-63 has been re-confirmed as a variable TeV $\gamma$-ray emitter. The firm detection of VHE photons emitted at a true anomaly $\theta$$\approx$-0.35 of the pulsar orbit, i.e. already ~50 days prior to the periastron passage, disfavors the stellar disc target scenario as a primary emission mechanism, based on current knowledge about the companion star's disc inclination, extension, and density profile. Results. VHE $\gamma$-ray emission from PSR B1259-63 was detected with an overall significance of 9.5 standard deviations using 55h of exposure, obtained from April to August 2007. The monthly flux of $\gamma$-rays during the observation period was measured, yielding VHE lightcurve data for the early pre-periastron phase of the system for the first time. No spectral variability was found on timescales of months. The spectrum is described by a power law with a photon index of $\Gamma$ = 2.8 $\pm$ 0.2stat $\pm$ 0.2sys and flux normalisation $\Phi_{0}$ = (1.1 $\pm$ 0.1stat $\pm$ 0.2sys) $\times$ 10-12 TeV-1 cm-2 s-1. PSR B1259-63 was also monitored in 2005 and 2006, far from periastron passage, comprising 8.9 h and 7.5 h of exposure, respectively. No significant excess of $\gamma$-rays is seen in those observations. Conclusions. PSR B1259-63 has been re-confirmed as a variable TeV $\gamma$-ray emitter. The firm detection of VHE photons emitted at a true anomaly $\theta$$\approx$-0.35 of the pulsar orbit, i.e. already ~50 days prior to the periastron passage, disfavors the stellar disc target scenario as a primary emission mechanism, based on current knowledge about the companion star's disc inclination, extension, and density profile.
Published: 2009
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2. Recent observations of VHE gamma rays from Cygnus X-3

Author: S. M. Rayner, D J Orford, K. E. Turver, V. G. Mannings, A. Carraminana, P. J. Edwards, P. M. Chadwick, K. T. S. Brazier, S.M. Bradbury, K. J. Orford, C. C. G. Bowden, Nigel Dipper, E. W. Lincoln, and T. J. L. McComb
Subjects: Physics, Telescope, Nuclear and High Energy Physics, High energy, Pulsar, law, Gamma ray, Northern Hemisphere, Astronomy, Astrophysics, Southern Hemisphere, Zenith, law.invention
Abstract: The authors' observations of Cygnus X-3 in 1981-88 have suggested that sporadic 12.6 ms pulsed very high energy gamma rays are produced at or near the maximum (phase 0.6) in the 4.8 h X-ray cycle. Cygnus X-3 was observed with the Durham University Mark IV Northern Hemisphere gamma-ray telescope in 1989, shortly after two radio outbursts were detected from the object. An analysis of these data suggests that 12.6 ms pulsar emission may be observed at a phase in the 4.8 h cycle some 1000 s before their prediction from previous measurements. This is in agreement with measurements made at Woomera by the University of Adelaide. More recent observations using the Mark III Southern Hemisphere telescope at large zenith angles have not provided any further evidence for pulsar activity.
Published: 1992
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3. Very High Energy Gamma Rays from Young Pulsars and Supernova Remnants in the Southern Hemisphere

Author: K. E. Turver, J. L. Osborne, P. M. Chadwick, T. J. L. McComb, K. Lyons, S. M. Rayner, K. J. Orford, and S. E. Shaw
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Pulsar planet, Gamma ray, Astronomy, Astronomy and Astrophysics, Astrophysics, Vela, Supernova, Neutron star, Pulsar, Space and Planetary Science, Millisecond pulsar, Southern Hemisphere, Astrophysics::Galaxy Astrophysics
Abstract: Observations have been made with the University of Durham Mark 6 telescope of a number of southern hemisphere supernova remnants and young pulsars (Vela pulsar, PSR B1055-52, PSR J1105-6107, PSR J0537-6910, and PSR B0540-69). No very high energy gamma-ray emission, either steady or pulsed, has been detected from these objects. The implications of these results for theories of high-energy gamma-ray production in plerions and young pulsars are discussed.
Published: 2000
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4. [Untitled]

Author: K. J. Orford, T. R. Kendall, K. Tindale, S. E. Hilton, S. P. Tummey, Nigel Dipper, M. D. Roberts, I. D. Roberts, J. Holder, M. Robertshaw, J. E. Dickinson, C. M. Moore, M. R. Dickinson, S. E. Shaw, W. Hogg, P. Cottle, P. Armstrong, T. J. L. McComb, K. E. Turver, S. M. Rayner, and P. M. Chadwick
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Astronomy and Astrophysics, Gamma-ray astronomy, law.invention, Telescope, Space and Planetary Science, law, High Energy Physics::Experiment, Astrophysics::Galaxy Astrophysics, Fermi Gamma-ray Space Telescope
Abstract: The design, construction and operation of the University of Durham ground-based gamma ray telescope is discussed. The telescope has been designed to detect gamma rays in the ≤ 200 GeV region and to achieve good discrimination between gamma ray and hadron initiated showers in the higher energy region (≳ 300 GeV). The telescope was commissioned in 1995 and a description of its design and operation is presented, together with a verification of the telescope's performance.
Published: 1999
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5. A burst of pulsed VHE gamma rays from AE Aquarii

Author: M. R. Dickinson, M. D. Roberts, S. M. Rayner, P. M. Chadwick, I. D. Roberts, K. J. Orford, K. E. Turver, T. J. L. McComb, S. P. Tummey, J. E. Dickinson, J. Holder, and Nigel Dipper
Subjects: Physics, Brightness, Phase (waves), Gamma ray, Astronomy, Flux, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Threshold energy, Luminosity, law.invention, Telescope, law
Abstract: We report the results of observations of AE Aquarii made on 25 occasions between July 1992 and October 1993 with the University of Durham very high energy (VHE) gamma-ray telescopes at Narrabri, N.S.W., Australia. The observations lasted for a total of 78 h and no persistent low-level pulsed emission was detected above an energy threshold of 350 GeV. However, an excess of pulsed VHE γ-rays was observed on 1993 October 11. The burst lasted for approximately 4200 s and occurred at phase 0.62–0.74 in the 9.88 h orbital cycle. The count rate excess was significant at the 0.99997 level and the periodicity was at the second harmonic of the 33 s period The hadron-induced background in the burst data has been suppressed by applying simple imaging techniques to those events recorded by an individual telescope and using trigonometric height of maximum analysis for the events recorded by two telescopes. These two independent results together provide evidence at a probability of chance occurrence of 10−7, after allowing for degrees of freedom, for the emission of a burst of pulsed γ-rays from AE Aquarii with threshold energy > 350 GeV, which show the characteristic features of γ-ray induced cascades. There is also some evidence to suggest that the brightness spectrum of Cerenkov events recorded during the burst is harder than that recorded in a sample of the background. The flux during the burst was approximately 4% of the total cosmic ray background at E> 350 GeV, corresponding to a peak pulsed luminosity of 1032 erg s−1
Published: 1995
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6. Discovery of VHE γ-rays from the BL Lacertae object PKS 0548-322

Author: Yvonne Becherini, A. Cheesebrough, S. M. Rayner, J. P. Vialle, G. Pedaletti, Joachim Ripken, A. Hoffmann, A. Förster, Martin Raue, J. F. Glicenstein, P.-O. Petrucci, B. Behera, L. Rob, Stefan Wagner, J. L. Skilton, G. Vasileiadis, D. Nekrassov, Michael Punch, J. Ruppel, M. K. Daniel, Christoph Deil, T. Kneiske, M. Kerschhagg, K. Egberts, Anna Szostek, Gilles Henri, L.-M. Chounet, P. M. Chadwick, G. Pelletier, L. Venter, A. C. Clapson, W. Domainko, P. H. Tam, Gerard Fontaine, A. Djannati-Ataï, A. Marcowith, Christo Venter, C. Jahn, Thomas Lohse, Guillaume Dubus, M. de Naurois, J. Brucker, G. Lamanna, F. Volp, M. Panter, U. Katz, E. Moulin, Tomasz Bulik, R. Moderski, M. Füssling, A. Zech, D. Hauser, Frank M. Rieger, T. J. L. McComb, F. Stinzing, A. Shalchi, A. Jacholkowska, B. Giebels, A. R. Bazer-Bachi, S. Schwemmer, S. Rosier-Lees, A. Charbonnier, F. Feinstein, D. Spangler, S. Heinz, Andrea Santangelo, R. C. G. Chaves, O. C. de Jager, J. M. Martin, P. Espigat, D. Khangulyan, W. Kluźniak, B. C. Raubenheimer, U. Barres de Almeida, S. Hoppe, A. Bochow, S. Schwarzburg, S. J. Nolan, D. Keogh, Jacek Niemiec, Jim Hinton, David Maurin, M. Vivier, L. O'c. Drury, C. Boisson, J-F. Olive, Dieter Horns, A. A. Zdziarski, Christian Stegmann, Stefan Ohm, Gavin Rowell, D. Gerbig, J.-P. Tavernet, Gisela Anton, S. Pita, C. B. Rulten, Francois Brun, C. van Eldik, Michal Ostrowski, J. Dyks, J.-P. Lenain, Stefano Gabici, D. Emmanoulopoulos, C. Farnier, Werner Hofmann, D. Nedbal, E. de Oña Wilhelm, G. Heinzelmann, Isak Delberth Davids, Regis Terrier, K. Kosack, Konrad Bernlöhr, A. Fiasson, B. Khélifi, G. Superina, Helene Sol, G. Hermann, G. Pühlhofer, Lukasz Stawarz, Michal Dyrda, K. J. Orford, M. Naumann-Godo, J. Bolmont, Rolf Bühler, Andreas Quirrenbach, B. Nicholas, V. Sahakian, Martin Ward, M. Sikora, Franky Dubois, Felix Aharonian, Reinhard Schlickeiser, F. M. Schöck, Riaan Steenkamp, M. Paz Arribas, Hugh Dickinson, Ullrich Schwanke, M. Dalton, Julien Masbou, M. C. Medina, A. G. Akhperjanian, Eckhard Kendziorra, V. Marandon, M. Hauser, M. Holleran, Heinrich J. Völk, M. Renaud, I. Jung, B. Rudak, Olivier Martineau-Huynh, B. Degrange, I. Büsching, Timothé Boutelier, Nu. Komin, P. Goret, Y. A. Gallant, Sarah Kaufmann, Pascal Vincent, L. Gérard, B. Glück, O. Tibolla, Wystan Benbow, Pierre Brun, D. Göring, V. Borrel, M. Tluczykont, R. Schröder, G. Coignet, Krzysztof Katarzynski, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESS, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris
Subjects: BL Lacertae objects: individual: PKS 0548-322, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Swift Gamma-Ray Burst Mission, Photon, Astrophysics::High Energy Astrophysical Phenomena, galaxies: active, Flux, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, law, 0103 physical sciences, 010303 astronomy & astrophysics, Physics, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Gamma ray, Astronomy, observations [gamma rays], Astronomy and Astrophysics, Synchrotron, individual: PKS 0548-322 [BL Lacertae objects], Crab Nebula, Space and Planetary Science, active [galaxies], Spectral energy distribution, gamma rays: observations, BL Lac object
Abstract: 6 pages, 3 figures; PKS 0548-322 (z=0.069) is a "high-frequency-peaked'' BL Lac object and a candidate very high energy (VHE, E>100 GeV) gamma-ray emitter, due to its high X-ray and radio flux. Observations at the VHE band provide insights into the origin of very energetic particles present in this source and the radiation processes at work. We report observations made between October 2004 and January 2008 with the H.E.S.S. array, a four imaging atmospheric-Cherenkov telescopes. Contemporaneous UV and X-ray observations with the Swift satellite in November 2006 are also reported. PKS 0548-322 is detected for the first time in the VHE band with H.E.S.S. We measure an excess of 216 gamma-rays corresponding to a significance of 5.6 standard deviations. The photon spectrum of the source is described by a power-law, with a photon index of Gamma=2.86 +/- 0.34 (stat) +/- 0.10 (sys). The integral flux above 200 GeV is 1.3 % of the flux of the Crab Nebula, and is consistent with being constant in time. Contemporaneous Swift/XRT observations reveal an X-ray flux between 2 and 10 keV of F_{2-10 keV}=2.3 +/- 0.2 x 10^{-11} erg.cm^{-2}. s^{-1}, an intermediate intensity state with respect to previous observations. The spectral energy distribution can be reproduced using a simple one-zone synchrotron self Compton model, with parameters similar those observed for other sources of this type.
Published: 2010
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7. Erratum to 'Observations of the Sagittarius dwarf galaxy by the HESS experiment and search for a dark matter signal' [Astropart. Phys. 29(1) (2008) 55--62]

Author: R. Schröder, C. van Eldik, D. Nedbal, Dimitrios Emmanoulopoulos, M. Holleran, S. M. Rayner, J. P. Vialle, G. Coignet, Seb. Funk, S. Schlenker, Conor Masterson, Michael Punch, J. L. Osborne, F. Feinstein, M. Lemoine-Goumard, D. Hauser, M. Beilicke, M. Panter, Luigi Costamante, A. Djannati-Ataï, Reinhard Schlickeiser, Wystan Benbow, A. R. Bazer-Bachi, Heinrich J. Völk, C. Stegmann, A. Shalchi, Rolf Bühler, P. H. Tam, I. Büsching, Kathrin Egberts, S. Schwarzburg, Felix Spanier, B. Degrange, Christian Farnier, Ullrich Schwanke, V. Sahakian, P. Vincent, L. Rolland, T. J. L. McComb, Alexandre Marcowith, O. C. de Jager, P. Espigat, Dieter Horns, Y. A. Gallant, Hugh Dickinson, T. Boutelier, A. Fiasson, C. Boisson, Martin Ward, Eric Nuss, A. G. Akhperjanian, Eckhard Kendziorra, S. Ranchon, M. Vivier, Gilles Henri, D. Spangler, David Berge, Stefan Wagner, Gerd Pühlhofer, C. Hadjichristidis, O. Martineau-Huynh, J.-P. Tavernet, R. Steenkamp, Felix Aharonian, P. M. Chadwick, Ilana M. Braun, Thomas Lohse, A. Lemiere, S. Pita, Guillaume Dubus, M. de Naurois, Helene Sol, M. Tluczykont, Svenja Carrigan, Guillaume Maurin, J. Ripken, B. Khélifi, G. Hermann, Regis Terrier, P.-O. Petrucci, L. Saugé, Werner Hofmann, Karl Kosack, I. J. Latham, G. Pelletier, J.-P. Olive, L.-M. Chounet, Stefan Funk, B. Giebels, S. Schwemmer, V. Borrel, Andrea Santangelo, Christo Venter, P. Goret, Luke O'c. Drury, B. C. Raubenheimer, E. Ferrero, Martin Raue, M. Füßling, Gavin Rowell, A. Hoffmann, G. Lamanna, B. Glück, A. Jacholkowska, A. M. Brown, E. Brion, J. F. Glicenstein, G. Fontaine, L. Rob, S. Hoppe, R. Le Gallou, M. Kerschhaggl, G. Vasileiadis, G. Heinzelmann, S. J. Nolan, J. M. Martin, M. Hauser, Nu. Komin, O. Bolz, Konrad Bernlöhr, G. Superina, Jim Hinton, K. J. Orford, R. Cornils, S. Rosier-Lees, E. Moulin, A. Noutsos, Faure, Alexandre, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Kernphysik (MPIK), Yerevan Physics Institute, Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Heinrich Heine Universität Düsseldorf = Heinrich Heine University [Düsseldorf], CERN [Genève], Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Physics, University of Durham, South Road, Unit for Space Physics, North-West University, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Dublin Institute for Advanced Studies (DIAS), Landessternwarte Königstuhl (LSW), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Humboldt University Of Berlin, Dr. Karl Remeis-Sternwarte, Astronomisches Institut, Universität Erlangen-Nuremberg, Eberhard Karls Universität Tübingen = Eberhard Karls University of Tuebingen, Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute of Particle and Nuclear Physics, Charles University (IPNP), University of Adelaide, Institut für Theoretische Physik, Ruhr-Universität Bochum, and University of Namibia
Subjects: Physics, 010308 nuclear & particles physics, Milky Way, Dark matter, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Signal, Dwarf spheroidal galaxy, Dark matter halo, 0103 physical sciences, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Sagittarius, Galaxy rotation curve, ComputingMilieux_MISCELLANEOUS, Dwarf galaxy
Abstract: International audience
Published: 2010
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8. 350 GeV gamma rays from AE Aqr

Author: S. M. Rayner, J. E. Dickinson, P. M. Chadwick, S.M. Bradbury, E. W. Lincoln, T. J. L. McComb, K. J. Orford, K. E. Turver, P. J. Edwards, C. C. G. Bowden, and Nigel Dipper
Subjects: Physics, Wavelength, Gamma ray, Astronomy, Astronomy and Astrophysics, Astrophysics, Dark period
Abstract: We report here the results of VHE γ-ray observations made during 1990 and 1991 using the Durham University Mark III and IV VHE γ-ray telescopes at Narrabri, N.S.W., Australia. There are 4 separate datasets, each obtained from observations over typically 10 days during a lunar dark period. The dataset from October 1990 exhibits periodicity at a chance probability of 1 × 10 -4 , and a similar effect is noted in the dataset from August 1991 at 1.6 × 10 −2 . In both cases, most of the power is in the second harmonic; the period is constant over at least 10 days and similar to that seen at optical wavelengths. No significant signal was detected in the September 1991 and October 1991 datasets. In addition, a strong and highly significant outburst lasting about 1 minute on 13 October 1990 and detected by two independent telescopes is reported. This outburst shows the 33 s periodic pulse structure and the pulses are in phase with those observed during the strongest sustained periodic signal in our data, from an observation lasting 3 h and taken 48 h previously. A second, weaker burst was also observed during August 1991.
Published: 1992
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9. Further observations of VHE gamma rays from Vela X-1

Author: E. W. Lincoln, T. J. L. McComb, S. M. Bradbury, C. C. G. Bowden, Nigel Dipper, K. E. Turver, P. J. Edwards, K. J. Orford, S. M. Rayner, J. E. Dickinson, and P. M. Chadwick
Subjects: Physics, Nuclear and High Energy Physics, Pulsar, Signal strength, Gamma ray, Astronomy, Astrophysics, Vela
Abstract: Observations of Vel X-1 were made in February 1991 using the University of Durham Mark III and IV VHE gamma-ray telescopes at Narrabri, New South Wales, Australia. The complete data-set shows evidence for weak but apparently constant periodicity at the X-ray pulsar period with a signal strength compatible with the authors' earlier measurements. In addition, on two occasions (February 13 and February 22 1991) they have evidence for short (1800 s) outbursts of emission of gamma rays modulated with the pulsar period. These outbursts occur at the same orbital phase (0.68), and the periodic effects noted during the outbursts have probabilities of change occurrence of 5.9*10-4 and 4.4*10-7.
Published: 1992
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10. Detection of Gamma Rays From a Starburst Galaxy

Author: S. Schwarzburg, J. Dyks, O. C. de Jager, Jim Hinton, U. Schwanke, Dmitry Khangulyan, Frank M. Rieger, M. K. Daniel, W. Kluźniak, M. Kerschhaggl, R. C. G. Chaves, J-F. Olive, K. J. Orford, S. Hoppe, M. Vivier, B. Behera, Stefan Ohm, Anna Szostek, F. Dubois, Petter Hofverberg, Dimitrios Emmanoulopoulos, L. Rob, Nu. Komin, Stefan Wagner, M. de Naurois, Gisela Anton, S. Schwemmer, P. Espigat, Alexandre Marcowith, Y. A. Gallant, P. Goret, J. Mehault, Andrea Santangelo, A. A. Zdziarski, M. Naumann-Godo, S. Rosier-Lees, Emmanuel Moulin, A. Charbonnier, F. Stinzing, G. Pedaletti, J.-P. Lenain, S. Heinz, J. Ripken, Francesca Volpe, M. Panter, B. Nicholas, Jacek Niemiec, M. Füßling, E. de Oña Wilhelmi, G. Fontaine, Olaf Reimer, J.F. Glicenstein, Sarah Kaufmann, U. Barres de Almeida, A. C. Clapson, F. Brun, L. Gérard, B. Glück, A. Djannati-Ataï, Tomasz Bulik, J. Ruppel, L.-M. Chounet, D. Klochkov, G. Vasileiadis, Guillaume Dubus, A. Jacholkowska, Michael Punch, J. Brucker, F. Feinstein, D. Göring, Olivier Martineau-Huynh, D. Keogh, A. Bochow, W. Domainko, P. H. Tam, Gavin Rowell, David Maurin, A. Fiasson, Julien Masbou, Thomas Lohse, V. Borrel, V. Sahakian, Michal Dyrda, Timothé Boutelier, Stefano Gabici, P.-O. Petrucci, Yvonne Becherini, S. J. Nolan, Rolf Bühler, Andreas Quirrenbach, G. Lamanna, Christian Farnier, B. C. Raubenheimer, M. Renaud, J. P. Tavernet, M. C. Medina, Dieter Horns, Konrad Bernlöhr, G. Superina, G. Pühlhofer, D. Nekrassov, Werner Hofmann, Michał Ostrowski, Fabio Acero, K. Katarzyński, A. R. Bazer-Bachi, B. Khélifi, German Hermann, Regis Terrier, Catherine Boisson, Christoph Deil, T. Kneiske, D. Gerbig, Gilles Henri, Pierre Brun, D. Nedbal, S. Pita, M. Tluczykont, P. Vincent, Martin Ward, Cameron B Rulten, M. Sikora, Felix Aharonian, Stephen Fegan, T. J. L. McComb, A. Hoffmann, K. Kosack, J. L. Skilton, Łukasz Stawarz, Heinrich J. Völk, C. van Eldik, L. Venter, G. Coignet, M. Hauser, D. Hauser, I. Büsching, A. Cheesebrough, R. Kossakowski, O. Tibolla, L. O'c. Drury, C. Stegmann, I. Jung, R. Steenkamp, B. Rudak, Kathrin Egberts, B. Degrange, G. Heinzelmann, J. Bolmont, Christo Venter, C. Jahn, U. F. Katz, R. Moderski, A. Zech, Reinhard Schlickeiser, Hugh Dickinson, V. Marandon, I. D. Davids, P. M. Chadwick, M. Raue, S. M. Rayner, J. P. Vialle, Guy Pelletier, B. Giebels, A. Förster, Helene Sol, F. M. Schöck, M. Paz Arribas, M. Dalton, A. G. Akhperjanian, A. Shalchi, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), HESS, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE), Astroparticle physics, Physics, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Multidisciplinary, 010308 nuclear & particles physics, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Gamma ray, FOS: Physical sciences, Astronomy, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Electromagnetic radiation, Galaxy, 3. Good health, Supernova, 0103 physical sciences, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics
Abstract: Starburst galaxies exhibit in their central regions a highly increased rate of supernovae, the remnants of which are thought to accelerate energetic cosmic rays up to energies of ~ 10^15 eV. We report the detection of gamma rays -- tracers of such cosmic rays -- from the starburst galaxy NGC 253 using the H.E.S.S. array of imaging atmospheric Cherenkov telescopes. The gamma-ray flux above 220 GeV is F = (5.5 +/- 1.0stat +/- 2.8sys) x 10^-13 ph. s-1 cm-2, implying a cosmic-ray density about three orders of magnitude larger than that in the center of the Milky Way. The fraction of cosmic-ray energy channeled into gamma rays in this starburst environment is 5 times larger than that in our Galaxy., 24 pages, 8 figures, published in Science Express, see: http://www.sciencemag.org/cgi/content/abstract/1178826
Published: 2009
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11. HESS upper limits on very high energy gamma-ray emission from the microquasar GRS 1915+105

Author: O. C. de Jager, S. Vorobiov, M. Vivier, Jim Hinton, G. Fontaine, Michael Punch, Joachim Ripken, Dmitry Khangulyan, M. Kerschhaggl, V. Sahakian, D. Keogh, Michał Ostrowski, Werner Hofmann, Stefan Wagner, Gisela Anton, M. Hauser, G. Pedaletti, J.-P. Lenain, M. K. Daniel, K. J. Orford, Francesca Volpe, A. Hoffmann, B. Nicholas, C. van Eldik, R. C. G. Chaves, Pierre Brun, M. Holleran, S. Hoppe, A. Shalchi, J. F. Glicenstein, A. C. Clapson, Guillaume Dubus, S. J. Nolan, Christian Farnier, D. Göring, Dieter Horns, P. M. Chadwick, Andreas Quirrenbach, S. Schwemmer, Gilles Henri, Frank M. Rieger, I. Büsching, S. Pita, S. Schwarzburg, Andrea Santangelo, A. A. Zdziarski, A. Djannati-Ataï, M. Tluczykont, L.-M. Chounet, M. Panter, D. Klochkov, Reinhard Schlickeiser, Rafal Moderski, Christoph Deil, Y. A. Gallant, T. Kneiske, Nu. Komin, B. Giebels, J. Dyks, A. Cheesebrough, Hugh Dickinson, W. Kluźniak, B. Behera, P. Goret, Jan Conrad, V. Marandon, L. Rob, P.-O. Petrucci, I. D. Davids, B. Khélifi, D. Nekrassov, Yvonne Becherini, G. Hermann, J. L. Skilton, Regis Terrier, W. Domainko, P. H. Tam, L. Fallon, A. Jacholkowska, Anna Szostek, F. Dubois, Christo Venter, D. Nedbal, Marek Sikora, M. Füßling, Petter Hofverberg, E. de Oña Wilhelmi, F. M. Schöck, G. Lamanna, C. Jahn, M. Paz Arribas, Sarah Kaufmann, U. F. Katz, G. Vasileiadis, V. Borrel, A. Zech, Ullrich Schwanke, S. M. Rayner, M. Dalton, L. Gérard, A. Charbonnier, Michal Dyrda, B. Glück, J. P. Vialle, Łukasz Stawarz, H. Sol, Cameron B Rulten, S. Heinz, P. Espigat, Tomasz Bulik, A. G. Akhperjanian, B. C. Raubenheimer, Guy Pelletier, R. Steenkamp, A. Förster, Martin Raue, O. Tibolla, M. Renaud, A. Fiasson, Thomas Lohse, Timothé Boutelier, A. R. Bazer-Bachi, Jacek Niemiec, Heinrich J. Völk, L. O'c. Drury, Olaf Reimer, G. Heinzelmann, Gavin Rowell, J. Bolmont, D. Gerbig, Felix Aharonian, J. Ruppel, Catherine Boisson, Peter Eger, Stephen Fegan, R. de los Reyes, J. Brucker, Emmanuel Moulin, M. Naumann-Godo, F. Stinzing, P. Vincent, C. Stegmann, Martin Ward, Felix Ryde, Iurii Sushch, R. Kossakowski, I. Jung, B. Rudak, Kathrin Egberts, B. Degrange, A. Bochow, S. Rosier-Lees, K. Kosack, Konrad Bernlöhr, G. Superina, G. Pühlhofer, Fabio Acero, Stefan Ohm, J-F. Olive, G. Coignet, K. Katarzyński, M. de Naurois, Alexandre Marcowith, J. Mehault, David Maurin, L. Venter, J.-P. Tavernet, T. J. L. McComb, F. Feinstein, F. Brun, Julien Masbou, Stefano Gabici, U. Barres de Almeida, A. Schönwald, M. C. Medina, Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), HESS, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Astrophysics::High Energy Astrophysical Phenomena, Context (language use), Astrophysics, 01 natural sciences, Luminosity, law.invention, Telescope, X-rays: binaries, Astrophysical jet, law, individuals: GRS 1915+105 [X-rays], 0103 physical sciences, 010303 astronomy & astrophysics, Cherenkov radiation, Astrophysics::Galaxy Astrophysics, X-rays: individuals: GRS 1915+105, Astroparticle physics, Physics, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Gamma ray, Astronomy, observations [gamma rays], Astronomy and Astrophysics, Particle acceleration, Space and Planetary Science, binaries [X-rays], gamma rays: observations
Abstract: Context. High energy particles reside in the relativistic jets of microquasars, making them possible sources of very high energy radiation (VHE, >100 GeV). Detecting this emission would provide a new handle on jet physics. Aims. Observations of the microquasar GRS 1915+105 with the HESS telescope array were undertaken in 2004-2008 to search for VHE emission. Methods. Stereoscopic imaging of Cherenkov radiation from extensive air showers is used to reconstruct the energy and direction of the incident gamma rays. Results. There is no evidence for a VHE gamma-ray signal either from the direction of the microquasar or its vicinity. An upper limit of $6.1\times 10^$ ph cm-2 s-1 (99.9% confidence level) is set on the photon flux above 410 GeV, equivalent to a VHE luminosity of ${\sim} 10^$ erg s-1 at 11 kpc. Conclusions. The VHE to X-ray luminosity ratio in GRS 1915+105 is at least four orders of magnitude lower than the ratio observed in gamma-ray binaries. The VHE radiative efficiency of the compact jet is less than 0.01% based on its estimated total power of 1038 erg s-1. Particle acceleration in GRS 1915+105 is not efficient at high energies and/or the magnetic field is too strong. It is also possible that VHE gamma-rays are produced by GRS 1915+105, but the emission is highly time-dependent.
Published: 2009
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12. HESS Observations and VLT Spectroscopy of PG 1553+113

Author: G. Heinzelmann, K. J. Orford, David Maurin, J.-P. Tavernet, J.-P. Lenain, W. Domainko, F. Schock, A. A. Zdziarski, P. H. Tam, Gerard Fontaine, J. Ripken, Michał Ostrowski, J. Ruppel, Gerd Pühlhofer, Gavin Rowell, A. Djannati-Ataï, Seb. Funk, R. Schröder, F. Dubois, Dimitrios Emmanoulopoulos, A. R. Bazer-Bachi, F. Feinstein, L. O'c. Drury, Felix Aharonian, V. Sahakian, B. Behera, Helene Sol, D. Spangler, Jean Michel Martin, Anne Lemiere, E. de Oña Wilhelmi, O. C. de Jager, Conor Masterson, L. Rob, P. Espigat, Nu. Komin, D. Nedbal, Luigi Costamante, Michael Punch, Christo Venter, C. Farnier, A. Fiasson, A. Shalchi, D. Keogh, P. Goret, Reinhard Schlickeiser, Karl Kosack, M. Vivier, A. Zech, G. Coignet, B. Khélifi, Hugh Dickinson, G. Hermann, Rolf Bühler, D. Hauser, Stefan Wagner, S. Schwarzburg, M. Füßling, M. Beilicke, G. Vasileiadis, Thomas Lohse, B. C. Raubenheimer, U. Barres de Almeida, Werner Hofmann, Martin Ward, B. Glück, Stefan Ohm, Wystan Benbow, S. M. Rayner, J. P. Vialle, Olivier Martineau-Huynh, S. Pita, A. C. Clapson, C. Hadjichristidis, J.-P. Olive, Dieter Horns, Timothé Boutelier, Ullrich Schwanke, M. Dalton, V. Borrel, A. Förster, Martin Raue, J. Dyks, J. L. Osborne, Regis Terrier, Guillaume Dubus, C. Boisson, Y. A. Gallant, A. G. Akhperjanian, Eckhard Kendziorra, P. M. Chadwick, M. Kerschhaggl, R. Steenkamp, Pascal Vincent, M. de Naurois, Heinrich J. Völk, K. Katarzynski, Gilles Henri, Rafal Moderski, Konrad Bernlöhr, Jim Hinton, B. Giebels, G. Superina, A. Hoffmann, E. Brion, J. F. Glicenstein, Matthieu Renaud, R. Cornils, S. Rosier-Lees, A. M. Brown, T. J. L. McComb, Svenja Carrigan, G. Pelletier, I. J. Latham, L. Stawarz, Emmanuel Moulin, C. Stegmann, I. Jung, B. Rudak, Kathrin Egberts, B. Degrange, S. Schwemmer, Andrea Santangelo, S. Ranchon, M. Panter, Ilana M. Braun, P.-O. Petrucci, Gilles Maurin, Tomasz Bulik, A. Jacholkowska, L. Rolland, M. Hauser, S. J. Nolan, C. van Eldik, M. Holleran, G. Lamanna, S. Hoppe, I. Büsching, O. Bolz, L.-M. Chounet, A. Marcowith, M. Lemoine-Goumard, G. Pedaletti, Francesca Volpe, Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), APC - Astrophysique des Hautes Energies (APC - AHE), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), AstroParticule et Cosmologie (APC (UMR_7164)), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), HESS, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), 10859748 - Holleran, Mathew, 12006653 - Venter, Christo, 10065857 - De Jager, Ocker Cornelis, 13235176 - Büsching, Ingo, and 10179240 - Raubenheimer, Barend Christoffel
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Flux, Astrophysics, 01 natural sciences, Spectral line, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], BL Lacertae objects: individual: PG1553+113 [galaxies], 0103 physical sciences, Emission spectrum, High Energy Stereoscopic System, Spectroscopy, 010303 astronomy & astrophysics, BL Lacertae objects: individual: PG 1553+113 [galaxies], Physics, Very Large Telescope, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), observations [gamma rays], Astronomy, Astronomy and Astrophysics, Redshift, Crab Nebula, Space and Planetary Science, active [galaxies]
Abstract: AIMS: The properties of the very high energy (VHE; E>100 GeV) gamma-ray emission from the high-frequency peaked BL Lac PG 1553+113 are investigated. An attempt is made to measure the currently unknown redshift of this object. METHODS: VHE Observations of PG 1553+113 were made with the High Energy Stereoscopic System (HESS) in 2005 and 2006. H+K (1.45-2.45 micron) spectroscopy of PG 1553+113 was performed in March 2006 with SINFONI, an integral field spectrometer of the ESO Very Large Telescope (VLT) in Chile. RESULTS: A VHE signal, ~10 standard deviations, is detected by HESS during the 2 years of observations (24.8 hours live time). The integral flux above 300 GeV is (4.6 +- 0.6{stat} +- 0.9{syst}) x 10^{-12} cm^{-2} s^{-1}, corresponding to ~3.4% of the flux from the Crab Nebula above the same threshold. The time-averaged energy spectrum is measured from 225 GeV to ~1.3 TeV, and is characterized by a very soft power law (photon index of Gamma = 4.5 +- 0.3{stat} +- 0.1{syst}). No evidence for any flux or spectral variations is found on any sampled time scale within the VHE data. The redshift of PG 1553+113 could not be determined. Indeed, even though the measured SINFONI spectrum is the most sensitive ever reported for this object at near infrared wavelengths, and the sensitivity is comparable to the best spectroscopy at other wavelengths, no absorption or emission lines were found in the H+K spectrum presented here., 9 pages, 12 Figures; Accepted for publication in Astronomy & Astrophysics; (Revision has simple typo in table 1 MJD column corrected.)
Published: 2008
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13. Enhancement of the gamma ray signal in atmospheric Cerenkov light measurements using the University of Durham VHE gamma ray telescopes

Author: Nigel Dipper, E. W. Lincoln, T. J. L. McComb, K. E. Turver, K. T. S. Brazier, P. M. Chadwick, A. Carraminana, K. J. Orford, S. M. Rayner, and V. G. Mannings
Subjects: Physics, Nuclear and High Energy Physics, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Cosmic ray, Field of view, Atomic and Molecular Physics, and Optics, law.invention, Telescope, Optics, Crab Nebula, Pulsar, law, business, Cherenkov radiation, Fermi Gamma-ray Space Telescope
Abstract: The design of two types of very high energy (VHE) gamma ray telescope which have the capability to enhance the gamma ray signal is discussed. The performance of the array of Cerenkov light telescopes operated at Dugway from 1981 – 1984 to provide within field of view arrival direction measurements from inter telescope fast timing is assessed, and is compared with that of a large telescope now operating at Narrabri which has focal plane detectors incorporating a coincidence “guard ring” system. We conclude that the coincidence guard ring technique applied to a large collecting area telescope offers the greater sensitivity.
Published: 1990
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14. 400 Gev gamma rays from the X-ray pulsar 1E2259+586

Author: E. W. Lincoln, T. J. L. McComb, K. T. S. Brazier, Nigel Dipper, S. M. Rayner, K. E. Turver, A. Carraminana, V. G. Mannings, K. J. Orford, and P. M. Chadwick
Subjects: Physics, Nuclear and High Energy Physics, Radiation flux, Pulsar, Gamma ray, Astronomy, Cosmic ray, Astrophysics, Electromagnetic radiation, Atomic and Molecular Physics, and Optics, Luminosity, X-ray pulsar, Fermi Gamma-ray Space Telescope
Abstract: We report observations of the X-ray pulsar 1E2259+586 made in 1988 October using the very high energy gamma ray telescope operating in La Palma. We find evidence significant at the 5.3 × 10 −5 level for the emission of 400 GeV gamma rays pulsating at 6.9790s. The flux of gamma rays is (2.0 ± 0.8) × 10 −10 cm −2 s −1 corresponding to VHE gamma ray luminosity of (5.3 ± 2.1) × 10 35 erg s −1 .
Published: 1990
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15. Observations of the Sagittarius Dwarf galaxy by the H.E.S.S. experiment and search for a Dark Matter signal

Author: M. Kerschhaggl, Michael Punch, Dimitrios Emmanoulopoulos, A. M. Brown, A. Noutsos, Svenja Carrigan, D. Hauser, R. Cornils, M. Beilicke, Felix Aharonian, I. J. Latham, G. Lamanna, L. Rolland, G. Pelletier, A. R. Bazer-Bachi, A. G. Akhperjanian, Eckhard Kendziorra, A. Lemiere, A. Shalchi, T. J. L. McComb, Felix Spanier, Konrad Bernlöhr, G. Superina, Wystan Benbow, R. Schröder, S. Schwarzburg, S. J. Nolan, Dieter Horns, M. Holleran, O. C. de Jager, G. Fontaine, S. Schwemmer, Emmanuel Moulin, S. Schlenker, U. Schwanke, Andrea Santangelo, V. Sahakian, M. Vivier, V. Borrel, P. Vincent, L.-M. Chounet, P. Espigat, C. van Eldik, I. Büsching, Conor Masterson, A. Djannati-Ataï, A. Marcowith, Ilana M. Braun, Stefan Wagner, G. Coignet, A. Fiasson, M. Raue, Heinrich J. Völk, Gilles Henri, S. M. Rayner, Martin Ward, J. P. Vialle, P.-O. Petrucci, Nu. Komin, S. Hoppe, Catherine Boisson, G. Heinzelmann, Rolf Bühler, E. Nuss, Y. A. Gallant, R. Le Gallou, C. Stegmann, B. Giebels, P. Goret, Helene Sol, K. J. Orford, B. C. Raubenheimer, R. Steenkamp, Kathrin Egberts, B. Degrange, O. Bolz, M. Hauser, Guillaume Maurin, Seb. Funk, German Hermann, P. H. Tam, B. Glück, S. Ranchon, G. Vasileiadis, P. M. Chadwick, Luigi Costamante, S. Rosier-Lees, M. Lemoine-Goumard, A. Hoffmann, Jim Hinton, S. Pita, Reinhard Schlickeiser, M. Tluczykont, D. Nedbal, Gavin Rowell, J.-P. Olive, E. Brion, K. Kosack, J. F. Glicenstein, M. Panter, Hugh Dickinson, Olivier Martineau-Huynh, J. P. Tavernet, Timothé Boutelier, Werner Hofmann, D. Spangler, E. Ferrero, C. Farnier, B. Khélifi, Regis Terrier, J. Ripken, L. Saugé, Stefan Funk, Gerd Pühlhofer, L. O'c. Drury, Jean Michel Martin, David Berge, A. Jacholkowska, J. L. Osborne, F. Feinstein, Thomas Lohse, M. de Naurois, C. Hadjichristidis, Christo Venter, M. Füssling, Guillaume Dubus, L. Rob, Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), HESS, Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Annecy de Physique des Particules (LAPP/Laboratoire d'Annecy-le-Vieux de Physique des Particules), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO)-AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Milky Way, Astrophysics::High Energy Astrophysical Phenomena, Dwarf galaxy problem, Dark matter, Astrophysics (astro-ph), Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, Dwarf spheroidal galaxy, Dark matter halo, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, 010303 astronomy & astrophysics, Galaxy rotation curve, Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract: Observations of the Sagittarius dwarf spheroidal (Sgr dSph) galaxy were carried out with the H.E.S.S. array of four imaging air Cherenkov telescopes in June 2006. A total of 11 hours of high quality data are available after data selection. There is no evidence for a very high energy gamma-ray signal above the energy threshold at the target position. A 95% C.L. flux limit of 3.6 x 10-12 cm-2s-1 above 250 GeV has been derived. Constraints on the velocity-weighted cross section are calculated in the framework of Dark Matter particle annihilation using realistic models for the Dark Matter halo profile of Sagittarius dwarf galaxy. Two different models have been investigated encompassing a large class of halo types. A 95% C.L. exclusion limit on of the order of 2 x 10-25 cm3s-1 is obtained for a core profile in the 100 GeV - 1 TeV neutralino mass range., Comment: 21 pages, 4 figures, 2 tables; Accepted for publication in Astroparticle Physics
Published: 2007
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16. Fast variability of tera-electron volt gamma rays from the radio galaxy M87

Author: Gilles Henri, S. Ranchon, S. Rosier-Lees, Christo Venter, B. C. Raubenheimer, R. Cornils, R. Schröder, Michael Punch, B. Giebels, S. Hoppe, Ullrich Schwanke, A. R. Bazer-Bachi, A. G. Akhperjanian, Eckhard Kendziorra, R. Steenkamp, Helene Sol, P. Goret, Karl Kosack, Nu. Komin, J. F. Glicenstein, O. Martineau-Huynh, J. L. Osborne, F. Feinstein, D. Hauser, A. Shalchi, M. Beilicke, L. Rob, Gerd Pühlhofer, Jim Hinton, O. Bolz, O. C. de Jager, L. O'c. Drury, E. Moulin, Catherine Boisson, M. Kerschhaggl, E. Ferrero, Seb. Funk, A. Fiasson, M. Ouchrif, S. Schwemmer, Andrea Santangelo, M. Lemoine-Goumard, M. Füßling, A. Djannati-Ataï, A. Noutsos, S. Schwarzburg, M. Panter, Dieter Horns, G. Lamanna, K. J. Orford, Gavin Rowell, Stefan Wagner, G. Vasileiadis, Luigi Costamante, Dimitrios Emmanoulopoulos, A. Lemiere, D. Nedbal, C. van Eldik, J.-P. Tavernet, C. Stegmann, Heinrich J. Völk, P. M. Chadwick, C. Hadjichristidis, Felix Spanier, S. Pita, J.-P. Lenain, V. Sahakian, Kathrin Egberts, S. J. Nolan, G. Fontaine, M. de Naurois, M. Holleran, S. Schlenker, Guillaume Dubus, Svenja Carrigan, M. Tluczykont, B. Degrange, A. M. Brown, L. Rolland, Conor Masterson, B. Khélifi, G. Hermann, Regis Terrier, I. J. Latham, Konrad Bernlöhr, G. Superina, A. Hoffmann, G. Coignet, Martin Raue, Y. A. Gallant, A. Reimer, P. Espigat, A. Konopelko, Rolf Bühler, J. Ripken, P. H. Tam, Reinhard Schlickeiser, V. Borrel, R. Le Gallou, I. Büsching, L. Saugé, Hugh Dickinson, P. Vincent, A. Marcowith, D. Spangler, A. Jacholkowska, Martin Ward, Guillaume Maurin, Ilana M. Braun, G. Heinzelmann, Stefan Funk, Jean Michel Martin, Felix Aharonian, T. J. L. McComb, David Berge, M. Hauser, Thomas Lohse, Wystan Benbow, L.-M. Chounet, S. M. Rayner, J. P. Vialle, Guy Pelletier, and Werner Hofmann
Subjects: Physics, Multidisciplinary, 010308 nuclear & particles physics, Radio galaxy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Electronvolt, Astronomy, Cosmic ray, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Cosmology, Black hole, 0103 physical sciences, Blazar, 010303 astronomy & astrophysics, Schwarzschild radius
Abstract: The detection of fast variations of the tera–electron volt (TeV) (10 12 eV) γ-ray flux, on time scales of days, from the nearby radio galaxy M87 is reported. These variations are about 10 times as fast as those observed in any other wave band and imply a very compact emission region with a dimension similar to the Schwarzschild radius of the central black hole. We thus can exclude several other sites and processes of the γ-ray production. The observations confirm that TeV γ rays are emitted by extragalactic sources other than blazars, where jets are not relativistically beamed toward the observer.
Published: 2006

17. Discovery of Very-High-Energy Gamma-Rays from the Galactic Centre Ridge

Author: V. Sahakian, Conor Masterson, Michael Punch, D. Hauser, M. Beilicke, A. Djannati-Ataï, C. Stegmann, Stefan Gillessen, G. Fontaine, Christo Venter, B. Degrange, Wystan Benbow, J. L. Osborne, F. Feinstein, Luigi Costamante, L. O'c. Drury, F. Breitling, Dieter Horns, M. Lemoine-Goumard, M. Tluczykont, A. M. Brown, Helene Sol, P. Espigat, N. Leroy, Gavin Rowell, Konrad Bernlöhr, R. Le Gallou, J.-P. Tavernet, P. M. Chadwick, M. Panter, L. Rolland, G. Pühlhofer, G. Heinzelmann, I. J. Latham, A. Reimer, Olaf Reimer, A. Lemiere, M. de Naurois, Nu. Komin, R. Cornils, S. J. Nolan, Martin Raue, M. Hauser, Ullrich Schwanke, P. Goret, A. G. Akhperjanian, S. M. Rayner, R. Steenkamp, C. G. Théoret, Jim Hinton, Guy Pelletier, Ilana M. Braun, Sven Klages, J. Raux, K. J. Orford, M. Siewert, C. van Eldik, O. Bolz, M. Holleran, A. Noutsos, P. Vincent, S. Schlenker, Werner Hofmann, Y. Fuchs, Felix Aharonian, T. J. L. McComb, A. Jacholkowska, A. Konopelko, Heinrich J. Völk, Gilles Henri, Reinhard Schlickeiser, Dimitrios Emmanoulopoulos, V. Borrel, Hugh Dickinson, A. R. Bazer-Bachi, B. Giebels, O. C. de Jager, Stefan Wagner, J. Ripken, L. Saugé, Stefan Funk, Jean Michel Martin, David Berge, Thomas Lohse, D. Spangler, Catherine Boisson, S. Pita, B. Khélifi, G. Hermann, Regis Terrier, Y. A. Gallant, C. Schuster, B. C. Raubenheimer, J. F. Glicenstein, O. Martineau-Huynh, L. Rob, M. Ouchrif, G. Vasileiadis, C. Hadjichristidis, Guillaume Dubus, L.-M. Chounet, A. Marcowith, Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), APC - Astrophysique des Hautes Energies (APC - AHE), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO), HESS, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, and Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Milky Way, Astrophysics::High Energy Astrophysical Phenomena, Acceleration, FOS: Physical sciences, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Sagittarius-A, 01 natural sciences, Emission, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Supernova remnant, 0103 physical sciences, Molecular clouds, Center region, Shell, High Energy Stereoscopic System, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Sagittarius A, Physics, Multidisciplinary, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Molecular cloud, Astrophysics (astro-ph), Astronomy, Mass, Galaxy, Supernova, Direction, 13. Climate action
Abstract: The origin of Galactic cosmic rays (with energies up to 10^15 eV) remains unclear, though it is widely believed that they originate in the shock waves of expanding supernova remnants. Currently the best way to investigate their acceleration and propagation is by observing the gamma-rays produced when cosmic rays interact with interstellar gas. Here we report observations of an extended region of very high energy (VHE, >100 GeV) gamma-ray emission correlated spatially with a complex of giant molecular clouds in the central 200 pc of the Milky Way. The hardness of the gamma-ray spectrum and the conditions in those molecular clouds indicate that the cosmic rays giving rise to the gamma-rays are likely to be protons and nuclei rather than electrons. The energy associated with the cosmic rays could have come from a single supernova explosion around 10,000 years ago., 8 pages, 3 figures, published in Nature
Published: 2006
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18. HESS observations of the galactic center region and their possible dark matter interpretation

Author: J.F. Glicenstein, L. Costamante, Nu. Komin, A. Djannati-Ataï, P. M. Chadwick, P. Goret, Luke O'c. Drury, A. Noutsos, M. Hauser, O. Bolz, M. de Naurois, A. Konopelko, Catherine Boisson, Wystan Benbow, Michael Punch, L. Rolland, Konrad Bernlöhr, G. Superina, Y. A. Gallant, C. van Eldik, J. L. Osborne, F. Feinstein, V. Borrel, P. Espigat, D. Hauser, M. Beilicke, Werner Hofmann, G. Pelletier, M. Holleran, A. Reimer, S. Schlenker, M. Ouchrif, L.-M. Chounet, S. J. Nolan, S. Pita, R. Cornils, F. Breitling, Dieter Horns, A. Marcowith, I. Büsching, Christo Venter, G. Heinzelmann, Gilles Henri, M. Tluczykont, D. Spangler, C. Stegmann, J. Ripken, L. Saugé, Olaf Reimer, R. Steenkamp, Stefan Funk, Kathrin Egberts, Svenja Carrigan, M. Raue, B. Degrange, Olivier Martineau-Huynh, E. Ferrero, Jean Michel Martin, Anne Lemiere, S. M. Rayner, M. Lemoine-Goumard, G. Vasileiadis, David Berge, A. Jacholkowska, B. Giebels, I. J. Latham, O. C. de Jager, Reinhard Schlickeiser, Ilana M. Braun, Hugh Dickinson, Gerd Pühlhofer, U. Schwanke, Thomas Lohse, M. Panter, B. Khélifi, Stefan Wagner, Regis Terrier, Felix Spanier, B. C. Raubenheimer, German Hermann, Jim Hinton, L. Rob, J.-P. Tavernet, C. Hadjichristidis, Guillaume Dubus, K. J. Orford, G. Fontaine, V. Sahakian, Rolf Bühler, Heinrich J. Völk, A. Fiasson, Gavin Rowell, R. Le Gallou, C. Masterson, Dimitrios Emmanoulopoulos, A. R. Bazer-Bachi, A. G. Akhperjanian, C. G. Théoret, Seb. Funk, A. M. Brown, Helene Sol, Felix Aharonian, Karl Kosack, T. J. L. McComb, P. Vincent, Martin Ward, D. Nedbal, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), APC - Astrophysique des Hautes Energies (APC - AHE), AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), HESS, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Dipartimento di Astronomia, Universita degli Studi di Bologna, Università di Bologna [Bologna] (UNIBO)-Università di Bologna [Bologna] (UNIBO), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)
Subjects: Photon, Point source, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics::High Energy Astrophysical Phenomena, Dark matter, 98.70.Rz, 95.35.+d, 95.85.Pw, 98.35.Jk, FOS: Physical sciences, General Physics and Astronomy, Flux, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Cherenkov radiation, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astrophysics (astro-ph), Galactic Center, Gamma ray, Astronomy, High Energy Physics::Experiment, Gamma-ray burst
Abstract: The detection of gamma-rays from the source HESS J1745-290 in the Galactic Center (GC) region with the H.E.S.S. array of Cherenkov telescopes in 2004 is presented. After subtraction of the diffuse gamma-ray emission from the GC ridge, the source is compatible with a point-source with spatial extent less than 1.2'(stat.) (95% CL). The measured energy spectrum above 160 GeV is compatible with a power-law with photon index of 2.25 +/- 0.04(stat.) +/- 0.10 (syst.) and no significant flux variation is detected. These measurements are discussed in the framework of dark matter annihilation. It is found that the bulk of the VHE emission must have non-dark-matter origin. Loose constraints on the velocity-weighted annihilation cross section are derived assuming the presence of an astrophysical non-dark-matter gamma-ray contribution., Comment: 5 pages, 2 figures, published in Physical Review Letters Correct some references The accepted version set on astro-ph was slightly too long for publication. This is a slightly shorter version
Published: 2005
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19. A low level of extragalactic background light as revealed by gamma-rays from blazars

Author: P. Espigat, Michael Punch, Olaf Reimer, D. Hauser, M. Beilicke, O. C. de Jager, F. Breitling, Dieter Horns, Wystan Benbow, Stefan Wagner, C. van Eldik, Y. Fuchs, M. Holleran, S. Schlenker, Felix Aharonian, J. Raux, Nu. Komin, Werner Hofmann, P. Goret, Jim Hinton, Gilles Henri, J.-P. Tavernet, Sven Klages, K. J. Orford, C. Hadjichristidis, Guillaume Dubus, V. Borrel, M. Panter, L. Rob, M. Ouchrif, M. de Naurois, M. Hauser, G. Vasileiadis, D. Spangler, A. Djannati-Ataï, B. Giebels, Christo Venter, A. Noutsos, V. Sahakian, T. J. L. McComb, P. M. Chadwick, A. Jacholkowska, Conor Masterson, Martin Raue, G. Fontaine, R. Le Gallou, N. Leroy, M. Siewert, C. Stegmann, Stefan Gillessen, B. C. Raubenheimer, R. Cornils, J. L. Osborne, L. Rolland, S. Pita, F. Feinstein, A. M. Brown, I. J. Latham, B. Degrange, P. Vincent, M. Lemoine-Goumard, B. Khélifi, G. Hermann, Regis Terrier, S. M. Rayner, S. J. Nolan, J. F. Glicenstein, O. Martineau-Huynh, Guy Pelletier, Dimitrios Emmanoulopoulos, G. Heinzelmann, M. Tluczykont, A. R. Bazer-Bachi, Konrad Bernlöhr, Heinrich J. Völk, G. Pühlhofer, A. Reimer, Ilana M. Braun, Luigi Costamante, A. Konopelko, L. O'c. Drury, Reinhard Schlickeiser, O. Bolz, Hugh Dickinson, Jean Michel Martin, Anne Lemiere, Gavin Rowell, David Berge, L.-M. Chounet, A. Marcowith, C. Schuster, Thomas Lohse, J. Ripken, L. Saugé, Stefan Funk, Y. A. Gallant, Catherine Boisson, C. G. Théoret, Helene Sol, Ullrich Schwanke, A. G. Akhperjanian, and R. Steenkamp
Subjects: media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Space, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Absorption, Universe, Spectrum, 0103 physical sciences, Galaxy formation and evolution, H1426+428, Blazar, 010303 astronomy & astrophysics, Telescope, Astrophysics::Galaxy Astrophysics, media_common, Physics, Multidisciplinary, 010308 nuclear & particles physics, 2Mass, Astrophysics (astro-ph), Astronomy, Stars, Redshift, Galaxy, Extragalactic background light, High-energy photons, Intergalactic travel, MKN 501
Abstract: The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the first stars, which may have formed before galaxy formation began. Direct measurements are difficult and not yet conclusive, owing to the large uncertainties caused by the bright foreground emission associated with zodiacal light. An alternative approach is to study the absorption features imprinted on the gamma-ray spectra of distant extragalactic objects by interactions of those photons with the background light photons. Here we report the discovery of gamma-ray emission from the blazars H 2356-309 and 1ES 1101-232, at redshifts z=0.165 and z=0.186, respectively. Their unexpectedly hard spectra provide an upper limit on the background light at optical/near-infrared wavelengths that appears to be very close to the lower limit given by the integrated light of resolved galaxies. The background flux at these wavelengths accordingly seems to be strongly dominated by the direct starlight from galaxies, thus excluding a large contribution from other sources -- in particular from the first stars formed. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought., 15 pages, 7 figures. Accepted by Nature, in press (April 20 issue). Replaced with published version. Title changed, text and figures rearranged with addition of Supplementary Information
Published: 2005

20. γ-Ray Generation in Microquasars: the link with AGN

Author: I. J. Latham, T. J. L. McComb, Klaus-Michael Aye, A. M. Brown, A. Noutsos, S. J. Nolan, S. M. Rayner, J. L. Osborne, C. Hadjichristidis, P. M. Chadwick, K. J. Orford, and R. Le Gallou
Subjects: Physics, High energy, Astrophysics::High Energy Astrophysical Phenomena, Astronomy, Spectral density, Quasar, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galactic nuclei, Synchrotron, law.invention, Astrophysical jet, law, Link (knot theory), Gamma-ray burst, Astrophysics::Galaxy Astrophysics
Abstract: The link between the physical processes responsible for high energy emission from relativistic jets in AGN and microquasars is investigated. A Fortran code based on an existing inhomogeneous, synchrotron self‐Compton (SSC) model, for AGN is presented. The code is then applied to the AGN 3C 279 and the microquasar LS5039. Spectral energy distributions (SED’s) are presented.
Published: 2005
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21. A new population of very high energy gamma-ray sources in the Milky Way

Author: G. Fontaine, R. Le Gallou, O. Bolz, M. Panter, Tulun Ergin, P. M. Chadwick, M. Hauser, O. C. de Jager, R. Cornils, I. J. Latham, P. Berghaus, U. Schwanke, J. Raux, G. Pühlhofer, P. Fleury, Michael Punch, L. O'c. Drury, I. Redondo, C. Stegmann, Stefan Gillessen, David Berge, Stefan Wagner, B. C. Raubenheimer, Klaus-Michael Aye, I. Jung, R. Steenkamp, M. Beilicke, C. G. Théoret, M. Raue, B. Degrange, L. Rob, A. R. Bazer-Bachi, Werner Hofmann, Thomas Lohse, M. Ouchrif, B. Khélifi, Wystan Benbow, S. M. Rayner, German Hermann, Catherine Boisson, P. Vincent, Helene Sol, Y. A. Gallant, J. L. Osborne, R. Terrier, F. Feinstein, A. Konopelko, Guy Pelletier, F. Breitling, Dieter Horns, A. Lemière, J. Ripken, A. Noutsos, B. Giebels, K. J. Orford, A. Djannati-Ataï, M. Holleran, Stefan Funk, S. Schlenker, S. Pita, C. Borgmeier, C. Hadjichristidis, P. Espigat, D. J. van der Walt, Christo Venter, Guillaume Dubus, A. G. Akhperjanian, Felix Aharonian, M. Tluczykont, T. J. L. McComb, Konrad Bernlöhr, Luigi Costamante, Olaf Reimer, Nu. Komin, M. de Naurois, J.-P. Tavernet, L. Saugé, A. Reimer, P. Goret, M. Lemoine, Jim Hinton, B. Visser, Reinhard Schlickeiser, A. Marcowith, Gavin Rowell, C. Schuster, V. Sahakian, Conor Masterson, G. Heinzelmann, L.-M. Chounet, G. Vasileiadis, N. Leroy, L. Rolland, S. J. Nolan, M. Siewert, J. Bussons Gordo, Heinrich J. Völk, Ilana M. Braun, Gilles Henri, A. M. Brown, AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), HESS, Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, education.field_of_study, Multidisciplinary, COSMIC cancer database, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Milky Way, Astrophysics::High Energy Astrophysical Phenomena, Population, Astrophysics (astro-ph), Gamma ray, Astronomy, FOS: Physical sciences, Cosmic ray, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galactic plane, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Pulsar, 0103 physical sciences, High Energy Stereoscopic System, education, 010303 astronomy & astrophysics
Abstract: Very high energy γ-rays probe the long-standing mystery of the origin of cosmic rays. Produced in the interactions of accelerated particles in astrophysical objects, they can be used to image cosmic particle accelerators. A first sensitive survey of the inner part of the Milky Way with the High Energy Stereoscopic System (HESS) reveals a population of eight previously unknown firmly detected sources of very high energy γ-rays. At least two have no known radio or x-ray counterpart and may be representative of a new class of “dark” nucleonic cosmic ray sources.
Published: 2005
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22. Calibration of cameras of the H.E.S.S. detector

Author: M. Panter, Wystan Benbow, Gilles Henri, J. Raux, G. Fontaine, David Berge, B. Khélifi, C. Borgmeier, G. Hermann, A. Djannati-Ataï, L-M. Chounet, Catherine Boisson, Nu. Komin, Felix Aharonian, Thomas Lohse, C. G. Théoret, P. Goret, I. Redondo, T. J. L. McComb, O. C. de Jager, B. Degrange, Y. A. Gallant, R. Le Gallou, C. Hadjichristidis, M. Siewert, V. Sahakian, S. M. Rayner, Martin Raue, M. de Naurois, O. Bolz, J. Ripken, L. Saugé, Michael Punch, B. C. Raubenheimer, Guy Pelletier, B. Giebels, A. Lemière, Stefan Wagner, Tulun Ergin, D. J. van der Walt, Stefan Funk, A. R. Bazer-Bachi, Conor Masterson, J.-P. Tavernet, P. Vincent, M. Beilicke, Jim Hinton, Helene Sol, I. J. Latham, S. Pita, J. L. Osborne, F. Feinstein, B. Visser, K. J. Orford, M. Lemoine, L. Rob, M. Ouchrif, Martin Pohl, P. M. Chadwick, Werner Hofmann, P. Espigat, Heinrich J. Völk, Luigi Costamante, Julien Guy, M. Rivoal, F. Breitling, Dieter Horns, Gerd Pühlhofer, Olaf Reimer, G. Heinzelmann, G. Vasileiadis, L. O'c. Drury, Klaus-Michael Aye, A. Konopelko, Ullrich Schwanke, Reinhard Schlickeiser, A. G. Akhperjanian, R. Steenkamp, A. Marcowith, P. Berghaus, Gavin Rowell, C. Schuster, A. M. Brown, M. Holleran, S. Schlenker, V. R. Chitnis, C. Stegmann, Stefan Gillessen, I. Jung, N. Leroy, L. Rolland, S. J. Nolan, M. Hauser, R. Cornils, P. Fleury, M. Tluczykont, Konrad Bernlöhr, A. Reimer, A. Noutsos, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESS, Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)
Subjects: High energy, Photomultiplier, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Optical-system, FOS: Physical sciences, Stereoscopy, Astrophysics, 01 natural sciences, Stability (probability), law.invention, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Optics, Atmospheric Cherenkov telescopes, law, 0103 physical sciences, Calibration, High Energy Stereoscopic System, Performance, 010303 astronomy & astrophysics, Cherenkov radiation, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, business.industry, Detector, Astrophysics (astro-ph), Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astronomy and Astrophysics, business
Abstract: H.E.S.S. - the High Energy Stereoscopic System- is a new system of large atmospheric Cherenkov telescopes for GeV/TeV astronomy. Each of the four telescopes of 107 m^2 mirror area is equipped with a 960-pixel photomulitiplier-tube camera. This paper describes the methods used to convert the photomultiplier signals into the quantities needed for Cherenkov image analysis. Two independent calibration techniques have been applied in parallel to provide an estimation of uncertainties. Results on the long-term stability of the H.E.S.S. cameras are also presented., Comment: 29 pages, 13 figures, accepted by Astroparticle Physics
Published: 2004
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23. High-energy particle acceleration in the shell of a supernova remnant

Author: V. Sahakian, Conor Masterson, B. Khélifi, C. Stegmann, Stefan Gillessen, R. Steenkamp, O. C. de Jager, U. Schwanke, R. Cornils, I. Redondo, M. de Naurois, I. J. Latham, D. J. van der Walt, J. L. Osborne, F. Feinstein, Stefan Wagner, S. Pita, O. Bolz, L. O'c. Drury, G. Heinzelmann, J. Ripken, L. Saugé, Y. A. Gallant, Tulun Ergin, Klaus-Michael Aye, P. Berghaus, N. Leroy, Jim Hinton, Gilles Henri, P. Espigat, G. Pühlhofer, Stefan Funk, B. Visser, K. J. Orford, M. Panter, M. Ouchrif, C. Schuster, David Berge, Nu. Komin, M. Holleran, Julien Guy, A. Djannati-Ataï, P. Goret, Michael Punch, S. Schlenker, A. Noutsos, L-M. Chounet, Catherine Boisson, Gavin Rowell, Thomas Lohse, V. R. Chitnis, P. Fleury, M. Beilicke, S. J. Nolan, A. Lemière, L. Rob, I. Jung, Olaf Reimer, Wystan Benbow, J. Raux, F. Breitling, Dieter Horns, Werner Hofmann, M. Tluczykont, Konrad Bernlöhr, A. Konopelko, A. R. Bazer-Bachi, M. Siewert, A. Marcowith, Reinhard Schlickeiser, A. Reimer, Luigi Costamante, M. Hauser, G. Vasileiadis, P. Vincent, B. Degrange, J. Bussons Gordo, C. Hadjichristidis, M. Lemoine, M. Rivoal, L. Rolland, Heinrich J. Völk, C. Borgmeier, Felix Aharonian, T. J. L. McComb, B. C. Raubenheimer, German Hermann, Martin Pohl, G. Fontaine, R. Le Gallou, M. Raue, S. M. Rayner, Guy Pelletier, B. Giebels, P. M. Chadwick, A. M. Brown, C. G. Théoret, Helene Sol, J.-P. Tavernet, A. G. Akhperjanian, Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF (institution))-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Pierre et Marie Curie - Paris 6 (UPMC), HESS, OpenMETU, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: System, High energy particle, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Cosmic ray, Astrophysics, Discovery, Cassiopeia-A, 01 natural sciences, Gamma-ray emission, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Spectrum, G347.3-0.5, 0103 physical sciences, origin, Cosmic-rays, 010306 general physics, Supernova remnant, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Origin, Multidisciplinary, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], SNR RX-J1713.7-3946, Astrophysics (astro-ph), Astronomy, Charged particle, Particle acceleration, Cassiopeia A, Interstellar medium, Supernova
Abstract: A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7-3946 (G347.3-0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy \gamma-rays of TeV energies (1 TeV=10^{12} eV). We present a TeV \gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks., Comment: 9 pages, 3 figures, published in Nature
Published: 2004
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24. TeV gamma rays from Geminga

Author: C. C. G. Bowden, K. J. Orford, K. E. Turver, Nigel Dipper, J. E. Dickinson, S. M. Bradbury, T. J. L. McComb, S. M. Rayner, and P. M. Chadwick
Subjects: Physics, Nuclear and High Energy Physics, Pulse period, Pulsar, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Flux, Astronomy, Astrophysics, Light curve, Positive correlation, Luminosity
Abstract: The bright gamma -ray source. Geminga has been identified as an X-ray and gamma -ray pulsar with a pulse period of 237 ms. Geminga was observed with the University of Durham very high-energy (VHE) gamma -ray telescopes at Dugway, Utah, in 1983. The analysis of these data has revealed pulsations at the X-ray/ gamma -ray pulse period, with the VHE gamma -ray pulses being in phase with the lower-energy gamma -ray pulses. The VHE and HE gamma -ray light curves are connected with a significance for positive correlation of 6*10-4. The VHE gamma -ray signal corresponds to a flux of about 3*10-11 cm-2 s-1 at energies greater than 1000 GeV, and a luminosity of 6*1030 erg s-1.
Published: 1993
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25. PKS 2155-304—A source of very high energy gamma rays

Author: S. E. Shaw, K. J. Orford, P. M. Chadwick, K. E. Turver, S. M. Rayner, T. J. L. McComb, J. L. Osborne, and K. Lyons
Subjects: PKS 2155-304, Physics, Telescope, High energy, law, Gamma ray, Astronomy, Astrophysics, Astronomical telescopes, Gamma-ray burst, Gamma ray detection, law.invention
Abstract: The University of Durham Mark 6 very high energy (VHE) γ-ray telescope has been used to observe the X-ray selected BL lac PKS 2155-304 in 1996, 1997 and 1998. The data show evidence for the emission of VHE γ-rays with E>300 GeV in 1996 September and 1997 October/November. There is evidence to support a correlation between the X-ray emission and VHE γ-ray emission. The strongest VHE emission was observed in 1997 November, when the object was producing the strongest high-energy X-ray emission ever recorded, and emission was also detected at E>100 MeV.
Published: 2001
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26. Very high energy gamma ray observations of southern hemisphere AGNs

Author: J. L. Osborne, T. J. L. McComb, K. E. Turver, K. Lyons, K. J. Orford, P. M. Chadwick, S. E. Shaw, and S. M. Rayner
Subjects: Physics, High energy, Gamma ray, Astronomy, Astronomical telescopes, Astrophysics, Galactic nuclei, Gamma-ray burst, Southern Hemisphere, Galaxy, Fermi Gamma-ray Space Telescope
Abstract: A range of AGNs visible from the Southern hemisphere has been observed with the University of Durham Mark 6 very high energy gamma ray telescope. Results of observations of 1ES 0323+022, PKS 0829+046, 1ES 1101-232, Cen A, PKS 1514-24, RKJ 10578-275, 1ES 2316-423, PKS 2005-489 and PKS 0548-322 are presented.
Published: 2001
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27. Geomagnetic effects on atmospheric Cherenkov images

Author: S. J. Nolan, T. J. L. McComb, K. J. Orford, K. Lyons, J. L. Osborne, M. K. Daniel, J. M. McKenny, P. M. Chadwick, and S. M. Rayner
Subjects: Physics, Physics::Instrumentation and Detectors, Cherenkov detector, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Cosmic ray, Gamma-ray astronomy, Astrophysics, Particle detector, Spectral line, law.invention, Earth's magnetic field, law, High Energy Physics::Experiment, Cherenkov radiation
Abstract: Atmospheric Cherenkov telescopes are used to detect electromagnetic showers from primary gamma rays and to discriminate these from cascades due to hadrons using the Cherenkov images. The geomagnetic field affects the development of showers and is shown to diffuse and distort the images and the effects should be included in interpreting the observations.
Published: 2001
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28. VHE observations of high energy peak BL Lacs

Author: P. M. Chadwick, J. M. McKenny, M. K. Daniel, S. M. Rayner, S. J. Nolan, J. L. Osborne, K. J. Orford, and T. J. L. McComb
Subjects: Physics, Telescope, High energy, Active galactic nucleus, law, Gamma ray, Flux, Astronomy, Gamma ray spectra, Astrophysics, Galactic nuclei, Cherenkov radiation, law.invention
Abstract: The Durham Mark 6 Cherenkov telescope has been used to observe a number of high energy peak BL Lacs (HBLs). Upper limits to the very high energy (VHE) gamma ray flux detected from PKS 0548−322, PKS 2005−489 and 1ES 1101−232 are presented. PKS 2155−304, which had previously been detected in VHE gamma rays, was observed in 1999. The data are consistent with possible bursts of VHE emission, but a final statement will only be possible once data from contemporary RXTE pointed observations are available. An upper limit for the average flux output during these observations is presented.
Published: 2001
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29. Very high energy gamma rays from Cen X-3

Author: J. L. Osborne, K. J. Orford, K. E. Turver, S. E. Shaw, T. J. L. McComb, K. Lyons, S. M. Rayner, and P. M. Chadwick
Subjects: Telescope, Physics, High energy, Variable source, Accretion (meteorology), law, X-ray binary, Gamma ray, Astronomy, Flux, Astrophysics, Gamma-ray burst, law.invention
Abstract: Cen X-3 is a well-studied high-mass accreting X-ray binary and a variable source of high energy gamma rays from 100 MeV to 1 TeV. The object has been extensively monitored with the University of Durham Mark 6 telescope. Results of observations, including those taken in 1998 and 1999, are reported. There is no evidence for time variability in the VHE data. There is also no evidence for correlation of the VHE flux with the X-ray flux detected by BATSE and RXTE/ASM. A search for periodic emission, at or close to the X-ray spin period, in the VHE data yielded a 3σ upper limit to the pulsed flux of 2.0×10−12 cm−12 s−1.
Published: 2001
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30. VHE gamma rays from binary systems

Author: Andrew Norton, S. M. Rayner, P. M. Chadwick, T. J. L. McComb, Sylvain Chaty, J. M. McKenny, M. K. Daniel, J. L. Osborne, K. J. Orford, Ulrich Kolb, Carole A. Haswell, and S. J. Nolan
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, X-ray binary, Binary number, Astronomy, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Gamma-ray astronomy, Astrophysics, Acceleration, Astrophysical jet, Astrophysics::Galaxy Astrophysics, Gamma ray detection
Abstract: With new generation VHE telescopes, X-ray binary systems become very promising targets for VHE γ-ray observations. In particular, if sources with relativistic jets are thought of as galactic analogues of AGNs, the acceleration mechanisms should be similar. We survey the prospects of studying these objects with HESS, particularly in the context of multiwavelength studies.
Published: 2001
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31. Flux limits for TeV emission from AGNs

Author: J. L. Osborne, S. M. Rayner, T. J. L. McComb, K. Lyons, K. J. Orford, S. E. Shaw, P. M. Chadwick, and K. E. Turver
Subjects: Physics, Telescope, Active galactic nucleus, law, Gamma ray, Flux, Astronomy, Gamma-ray astronomy, Astrophysics, Galactic nuclei, Southern Hemisphere, Gamma ray detection, law.invention
Abstract: The University of Durham Mark 6 telescope has been used to make observations of a number of AGNs visible from the Southern Hemisphere. Limits to VHE gamma ray emission from IES 0323+022, PKS 0829+046, IES 1101−232, Cen A, PKS 1514−24, RXJ 10578−275 and IES 2316−423 are presented, both for steady emission and for outbursts on timescales of ∼1 day.
Published: 2000
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32. TeV emission from supernovae

Author: J. L. Osborne, P. M. Chadwick, S. M. Rayner, K. J. Orford, T. J. L. McComb, K. E. Turver, K. Lyons, and S. E. Shaw
Subjects: Telescope, Physics, Supernova, law, Gamma ray, Astronomy, Astrophysics, Gamma-ray astronomy, Limit (mathematics), Near-Earth supernova, law.invention
Abstract: Observations have been made with the University of Durham Mark 6 telescope of SN 1006 and SN 1998bw. Limits to VHE gamma ray emission from these objects have been derived. The upper limit from SN 1006 may be in conflict with the measurement made with the CANGAROO telescope.
Published: 2000
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33. Geomagnetic effects on the performance of atmospheric Čerenkov telescopes

Author: S. E. Shaw, S. M. Rayner, P. M. Chadwick, J. L. Osborne, T. J. L. McComb, K. Lyons, K. J. Orford, and K. E. Turver
Subjects: Physics, Field (physics), Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Hadron, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, FOS: Physical sciences, Astronomy, Electron, Gamma-ray astronomy, Astrophysics, Earth's magnetic field, Cascade, Distortion, High Energy Physics::Experiment, Nuclear Experiment
Abstract: Atmospheric Cerenkov telescopes are used to detect electromagnetic showers from primary gamma rays of energy > 300 GeV and to discriminate these from cascades due to hadrons using the shape and orientation of the Cerenkov images. The geomagnetic field affects the development of showers and diffuses and distorts the images. When the component of the field normal to the shower axis is sufficiently large (> 0.4 G) the performance of gamma ray telescopes may be affected., 4 pages, 5 figures, to appear in the Proceedings of 26th International Cosmic Ray Conference (Salt Lake City, 1999)
Published: 2000
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34. Very high energy gamma rays from X-ray binaries

Author: J. L. Osborne, K. J. Orford, S. M. Rayner, T. J. L. McComb, K. Lyons, P. M. Chadwick, K. E. Turver, and S. E. Shaw
Subjects: Physics, High energy, Pulsar, Astrophysics::High Energy Astrophysical Phenomena, Stellar rotation, X-ray, X-ray binary, Gamma ray, Astronomy, Gamma-ray astronomy, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: We have reported the discovery of VHE gamma ray emission from the X-ray binary Cen X-3. We report further VHE observations of this object taken in 1998 and 1999. While these new data also show VHE gamma ray emission, no evidence of modulation at either the orbital or pulsar periods is found.
Published: 2000
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35. A search for VHE gamma rays from young pulsars and supernova remnants in the Southern Hemisphere

Author: K. E. Turver, T. J. L. McComb, K. Lyons, S. E. Shaw, J. L. Osborne, K. J. Orford, S. M. Rayner, and P. M. Chadwick
Subjects: Physics, Neutron star, Supernova, Pulsar, Millisecond pulsar, Pulsar planet, Astronomy, Astrophysics, Magnetar, Vela, Near-Earth supernova
Abstract: Observations have been made with the University of Durham Mark 6 telescope of a number of supernova remnants and young pulsars (PSR B1706-44, Vela pulsar, PSR B1055-52, PSR J1105-6107, PSR J0537-6910 and PSR B0540-69). Although steady emission has been seen from PSR B1706-44, no VHE gamma ray emission, either steady or pulsed, has been detected from the other objects. Implications of these results for theories of high energy gamma ray production in plerions and young pulsars are discussed.
Published: 2000
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36. Flux limits for TeV emission from pulsars

Author: K. J. Orford, P. M. Chadwick, K. E. Turver, J. L. Osborne, S. E. Shaw, T. J. L. McComb, K. Lyons, and S. M. Rayner
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, Astrophysics, Gamma-ray astronomy, Near-Earth supernova, Vela, Magnetar, law.invention, Telescope, Supernova, Pulsar, law, Astrophysics::Galaxy Astrophysics
Abstract: Observations have been made with the University of Durham Mark 6 telescope of a number of Southern hemisphere supernova remnants and young pulsars (Vela pulsar, PSR B1055−52, PSR J1105−6107, PSR J0537−6910 and PSR B0540−69). No VHE gamma ray emission, either steady or pulsed, has been detected from these objects. The implications of these results for theories of high energy gamma ray production in plerions and young pulsars are discussed.
Published: 2000
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37. Sensing atmospheric conditions using MIR radiometers

Author: T. J. L. McComb, K. Lyons, J. L. Osborne, K. J. Orford, S. E. Shaw, K. E. Turver, S. M. Rayner, and P. M. Chadwick
Subjects: Physics, Radiometer, Astrophysics::High Energy Astrophysical Phenomena, media_common.quotation_subject, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, Gamma-ray astronomy, Temperature measurement, law.invention, Telescope, law, Sky, Astrophysics::Earth and Planetary Astrophysics, Astronomical telescopes, Astrophysics::Galaxy Astrophysics, Remote sensing, media_common, Fermi Gamma-ray Space Telescope
Abstract: MIR (8–14 μm) radiometers have been used to sense the temperature of the sky as a measure of cloud and other obscurants in the field of an atmospheric Cerenkov telescope. Comparisons between the MIR signature and the performance of the Mark 6 gamma ray telescope are reported.
Published: 2000
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38. VHE gamma ray observations of Southern hemisphere AGNs

Author: K. E. Turver, K. J. Orford, J. L. Osborne, S. E. Shaw, P. M. Chadwick, S. M. Rayner, T. J. L. McComb, and K. Lyons
Subjects: Red shift, Physics, High energy, Active galactic nucleus, Gamma ray, Astronomy, Gamma-ray astronomy, Astrophysics, Galactic nuclei, Southern Hemisphere, Fermi Gamma-ray Space Telescope
Abstract: A range of AGNs visible from the Southern hemisphere has been observed with the University of Durham Mark 6 very high energy gamma ray telescope. Results of the observations of PKS 2155−304, 1ES 0323+022, PKS 0829+046, 1ES 1101−232, Cen A, PKS 1514−24, RXJ 10578−275, 1ES 2316−423, PKS 2005−489 and PKS 0548−322 are presented.
Published: 2000
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39. TeV emission from PKS 2155−304

Author: K. J. Orford, J. L. Osborne, S. E. Shaw, K. E. Turver, T. J. L. McComb, K. Lyons, S. M. Rayner, and P. M. Chadwick
Subjects: Physics, PKS 2155-304, High energy, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Astronomy, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Gamma-ray astronomy, Astrophysics, Fermi Gamma-ray Space Telescope, Gamma ray detection
Abstract: The X-ray selected BL Lac PKS 2155−304 has been observed using the University of Durham Mark 6 very high energy gamma ray telescope during 1998. We find no evidence for TeV emission during these recent observations when the X-ray flux was observed to be low. We have reconsidered our measurements made in 1997 November when PKS 2155−304 was in a bright X-ray state and extended X-ray and GeV gamma ray observations were made as part of a multiwavelength campaign. Comparisons are made of the VHE emission during this time with the available data from other wavelengths.
Published: 2000
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40. SN1987a - updated limit to 400 GeV gamma ray emission using the narrabri VHE gamma ray telescope - May 1989

Author: K. J. Orford, K. E. Turver, E. W. Lincoln, S. M. Rayner, T. J. L. McComb, P. M. Chadwick, K. T. S. Brazier, Nigel Dipper, and A. Carraminana
Subjects: Physics, Nuclear and High Energy Physics, Stars, Supernova, Binary star, Gamma ray, Astronomy, Cosmic ray, Astrophysics, Variable star, Electromagnetic radiation, Atomic and Molecular Physics, and Optics, Fermi Gamma-ray Space Telescope
Abstract: A search for 400 GeV gamma rays from SN 1987a has been conducted using the Narrabri gamma ray telescope, starting with a fortuitous observation within 5 hours of the core collapse in 1987 February. A more extensive program of observations up to 1988 April has been reported by us 1 . A luminosity limit of 4 × 10 38 erg s −1 (significant at the 3 SD level) was obtained for the emission of gamma rays of energy > 400 GeV immediately following the collapse. Subsequent observations throughout 1987 indicate continued validity of this limit. In 1988 January–February, as the possibility of the penetration of VHE gamma rays increased, a series of observations provided a limit to the luminosity of 7×10 37 erg s −1 . We here report the results of continuing observations up to 1989 May.
Published: 1990
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41. The University of Durham Mark 6 VHE gamma ray telescope

Author: T. R. Kendall, S. E. Shaw, P. M. Chadwick, K. E. Turver, K. J. Orford, T. J. L. McComb, I. D. Roberts, S. M. Rayner, Jamie Holder, M. R. Dickinson, and Nigel Dipper
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Astrophysics, law.invention, Telescope, law, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Astronomical telescopes, Gamma detection, Astrophysics::Galaxy Astrophysics, Fermi Gamma-ray Space Telescope, Gamma ray detection
Abstract: The operation of the University of Durham Mark 6 atmospheric Cerenkov telescope is discussed. The telescope has been used to detect gamma rays at energies ⩾150 GeV and to achieve good discrimination between gamma ray and hadron initiated showers, using both conventional imaging and novel fluctuation measures. The telescope was commissioned in 1995 and a description of its operation is presented. Verification of the performance during observations of PSR B1706-44 is described.
Published: 1997
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42. VHE gamma rays from PSR B1706-44

Author: Nigel Dipper, K. J. Orford, I. D. Roberts, S. E. Shaw, J. L. Osborne, K. E. Turver, P. M. Chadwick, Jamie Holder, T. J. L. McComb, S. M. Rayner, M. R. Dickinson, and T. R. Kendall
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Extrapolation, Gamma ray, Astronomy, Flux, Gamma ray spectra, Astrophysics, law.invention, Telescope, Pulsar, law, Spectral slope, High Energy Physics::Experiment, Nuclear Experiment, Gamma-ray burst
Abstract: Observations made with the University of Durham Mark 6 atmospheric Cerenkov telescope confirm that PSR B1706-44 is a VHE γ-ray emitter. The γ-ray flux has been measured at 250 GeV, and suggests a spectral slope that is consistent with extrapolation from the sub-10 GeV region. There is no indication from our dataset that the VHE γ-rays are pulsed, in contrast to the findings at
Published: 1997
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43. A ground based installation for the detection of gamma rays with energy 50–2000 GeV

Author: K. E. Turver, P. Cottle, S. Dye, M. Robertshaw, S. M. Rayner, Nigel Dipper, S. M. Bradbury, P. M. Chadwick, K. J. Orford, K. Tindale, J. E. Dickinson, C. C. G. Bowden, D. G. Roff, E. W. Lincoln, T. J. L. McComb, J. L. Osborne, W. Hogg, S. E. Hilton, and K. Parkin
Subjects: Nuclear physics, Physics, Observatory, Gamma ray, Astronomy, Gamma detection, Energy (signal processing)
Abstract: This paper describes the University of Durham ground‐based gamma ray programme for the 1990s, and improvements being made to the Cerenkov Observatory at Narrabri, N. S. W.
Published: 1994
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44. Primary particle acceleration above 100 TeV in the shell-type supernova remnant RX J1713.7 − 3946 with deep H.E.S.S. observations (Corrigendum)

Author: Felix Spanier, A. Konopelko, Seb. Funk, S. Hoppe, L. Rolland, S. J. Nolan, M. de Naurois, Reinhard Schlickeiser, Svenja Carrigan, I. J. Latham, Gavin Rowell, Nu. Komin, D. Nedbal, Ilana M. Braun, Luigi Costamante, Hugh Dickinson, P. Espigat, O. Bolz, A. Jacholkowska, M. Kerschhaggl, R. Schroeder, J. Ripken, M. Panter, B. Khélifi, P. M. Chadwick, A. Shalchi, Olaf Reimer, L. Saugé, P. Goret, O. C. de Jager, Felix Aharonian, Y. A. Gallant, S. Schwarzburg, Christo Venter, Michael Punch, Stefan Funk, Dimitrios Emmanoulopoulos, K. Bernloehr, G. Heinzelmann, S. Pita, Ullrich Schwanke, I. Buesching, Conor Masterson, F. Feinstein, V. Sahakian, D. Spangler, Stefan Wagner, M. Tluczykont, G. Lamanna, A. G. Akhperjanian, Eckhard Kendziorra, D. Hauser, A. Djannati-Ataï, Riaan Steenkamp, Wystan Benbow, Martin Ward, G. Superina, M. Beilicke, L. Rob, A. Marcowith, J. L. Osborne, M. Fuessling, Regis Terrier, A. Reimer, S. M. Rayner, J. P. Vialle, Martin Raue, J. M. Martin, E. Ferrero, M. Lemoine-Goumard, E. Moulin, Guy Pelletier, Karl Kosack, S. Schwemmer, G. Vasileiadis, G. Coignet, Andrea Santangelo, L-M. Chounet, V. Borrel, A. Noutsos, Olivier Martineau-Huynh, P. H. Tam, Gerard Fontaine, C. Hadjichristidis, A. Fiasson, R. Cornils, Guillaume Dubus, B. Glueck, Dieter Horns, R. Le Gallou, S. Rosier-Lees, R. Buehler, Werner Hofmann, Jim Hinton, H. Sol, L. O'c. Drury, K. J. Orford, T. J. L. McComb, B. C. Raubenheimer, A. M. Brown, J.-P. Tavernet, German Hermann, G. Puehlhofer, A. Hoffmann, E. Brion, J. F. Glicenstein, Gilles Henri, B. Giebels, C. Boisson, A. R. Bazer-Bachi, Heinrich J. Völk, P. Vincent, Anne Lemiere, David Berge, Thomas Lohse, J-P. Olive, Gilles Maurin, M. Hauser, C. van Eldik, S. Ranchon, M. Holleran, S. Schlenker, C. Stegmann, Kathrin Egberts, and B. Degrange
Subjects: Physics, Particle acceleration, Space and Planetary Science, Primary (astronomy), Shell (structure), Astronomy, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Supernova remnant
Published: 2011
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45. New measurements of the 12.6 millisecond pulsar in Cygnus X-3

Author: K. E. Turver, J. H. Turver, P. C. Mackie, E. W. Lincoln, T. J. L. McComb, A. Carraminana, P. M. Chadwick, K. T. S. Brazier, S. M. Rayner, K. J. Orford, Nigel Dipper, and V. G. Mannings
Subjects: Physics, Stars, Pulsar, Space and Planetary Science, Millisecond pulsar, Binary star, X-ray binary, Astronomy, Astronomy and Astrophysics, Astrophysics, Gamma-ray astronomy, Ephemeris, Stellar pulsation
Abstract: Evidence for a 12.59 ms pulsar in Cygnus X-3 is presented on the basis of TeV gamma-ray observations. Evidence for pulsed emission at a phase in the 4.8 hr cycle and with a pulsar period and secular period derivative are compatible with earlier measurements (Chadwick et al., 1985). The conservative overall Rayleigh probability of uniformity of phase for this new result is 1.7 x 10 to the -6th. Data from observations of Cygnus X-3 from 1981 to 1985 are analyzed using a new X-ray ephemeris of the 4.8 hr X-ray cycle. This suggests that Cygnus X-3 is producing sporadic very high energy gamma rays at a fixed time in the 4.8 hr X-ray cycle. 28 refs.
Published: 1990
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46. Ĉerenkov radiation in large cosmic-ray air showers

Author: K. E. Turver, K. J. Orford, J. A. L. Shearer, D. W. Wellby, W. D. Waddoup, R. T. Hammond, and R. J. Protheroe
Subjects: Physics, Photomultiplier, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Cosmic ray, Astrophysics, Radiation, Atmosphere, Density distribution, Cascade, Cherenkov radiation, Zenith
Abstract: A synchronized array of fast photomultipliers has been used to reconstruct the image in Ĉerenkov light of individual large cosmicray showers high in the atmosphere. The details of the images are in agreement with simulations based upon conservative models for cascade development. Observation of the fluctuations of the image between showers may enable the mass of the energetic cosmic rays to be determined.
Published: 1978
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47. The University of Durham Southern Hemisphere VHE gamma ray telescope

Author: A. Carraminana, K. E. Turver, V. G. Mannings, K. J. Orford, K. T. S. Brazier, P. M. Chadwick, E. W. Lincoln, T. J. L. McComb, Nigel Dipper, S. M. Rayner, and T. R. Currell
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma ray, Astronomy, Astronomy and Astrophysics, Gamma-ray astronomy, Astrophysics, Coincidence, law.invention, Telescope, Space and Planetary Science, law, Southern Hemisphere, Cherenkov radiation, Zenith, Fermi Gamma-ray Space Telescope
Abstract: The design of very high energy (VHE) gamma ray telescopes is discussed and it is shown that a triple-mirror telescope operating in threefold fast coincidence provides an effective instrument. The design, construction and operation of a large VHE gamma ray telescope with an energy threshold of 300 GeV (at the zenith) and incorporating several novel features is described. The use of a coincidence ‘guard ring’ technique is shown to result in the rejection of about 50% of the off-source (proton) events which form a high background and limit the sensitivity of such telescopes.
Published: 1989
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48. Evidence for the free precession of a neutron star

Author: K. J. Orford
Subjects: Physics, Astrophysics::High Energy Astrophysical Phenomena, X-ray binary, Astronomy, Astronomy and Astrophysics, Astrophysics, Binary pulsar, Neutron star, Amplitude, Pulsar, Space and Planetary Science, Binary star, Precession, Astrophysics::Galaxy Astrophysics, X-ray pulsar
Abstract: Although the free precession of a neutron star has been put forward as the cause of long-period variations in some X-ray pulsar emissions, no corroborating evidence has been found. The recent observation of a pulsar in Cygnus X-3, a system with a well measured long-period variation, provides an opportunity to examine the possibility of free precession. The properties of the pulsar which have been observed so far are consistent with the neutron star having a small free precession amplitude.
Published: 1987
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49. Association of the 6-ms pulsar PSR1953 with the COS-B γ-ray source 2CG065

Author: K. J. Orford, I. W. Kirkman, K. E. Turver, J. C. Dowthwaite, P. M. Chadwick, A. B. Harrison, and T. J. L. McComb
Subjects: Physics, Stars, Multidisciplinary, Pulsar, Binary star, Astronomy, Astrophysics, Gamma-ray astronomy, Light curve, Ephemeris, Orbital period, Electromagnetic radiation
Abstract: A systematic search for fast radio pulsars in the error boxes of the low energy γ-ray sources detected by the COS-B collaboration led to the discovery1 of a 6.1-ms radio pulsar PSR1953 + 29 in a binary system with orbital period of 120±4 days inside the error box of 2CG065 + 0. It was not possible to associate unambiguously the two objects without either a precise position for the γ-ray source or the detection of 6.1-ms pulsed γ rays. Following the determination of a more accurate orbital ephemeris for the radio pulsar, we have examined our data for evidence for pulsed TeV γ rays. Here, we report the detection of such γ rays with the characteristic 6.1-ms periodicity of the radio pulsar. The γ rays were detected using the ground-based atmospheric Cerenkov technique at the University of Durham γ-ray facility at Dugway, Utah2. This result, significant at the 5.4σ level, provides evidence for the association of the 6-ms radio pulsar PSR1953 + 29 with the γ-ray source 2CG065 + 0.
Published: 1985
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50. Development of Atmospheric Cosmic-Ray Showers

Author: K. J. Orford and K. E. Turver
Subjects: Atmospheric radiation, Physics, Range (particle radiation), Atmosphere of Earth, Primary (astronomy), General Physics and Astronomy, Astronomy, Cosmic ray, Astrophysics, Mass composition, Space radiation, Cherenkov radiation
Abstract: In a recent paper Thornton and Clay strongly suggest a very early development in the atomosphere for small cosmic-ray showers and consequently require a change in primary mass composition in the energy range 10/sup 15/--10/sup 17/ eV. It is suggested here that when allowance is made for inconsistencies in the data the necessity for the early development of small showers: and hence the inferred rapid change in primary composition: is removed.
Published: 1980
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