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          Institute: MPI für Kernphysik     Collection: High-Energy Astrophysics     Display Documents



  history
ID: 276608.0, MPI für Kernphysik / High-Energy Astrophysics
A low level of extragalactic background light as revealed by gamma-rays from blazars
Authors:Aharonian, F.; Akhperjanian, A. G.; Bazer-Bachi, A. R.; Beilicke, M.; Benbow, W.; Berge, D.; Borrel, V.; Bernlöhr, K.; Bolz, O.; Boisson, C:; Glicenstein, J.F.; Breitling, F.; Brown, A. M.; Dickinson, H.J.; Chadwick, P. M.; Braun, I.; Chounet, L.-M.; Cornils, R.; Costamante, L.; Degrange, B.; Djannati-Atai, A.; Drury, L.O'C.; Emmanoulopoulos, D.; Espigat, P.; Feinstein, F.; Jacholkowska, A.; Fontaine, G.; Funk, S.; Gallant, Y. A.; Giebels, B.; Gillessen, S.; Goret, P.; Dubus, G.; Hadjichristidis, C.; Hauser, M.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Holleran, M.; Horns, D.; de Jager, O. C.; Khélifi, B.; Komin, N.; Konopelko, A.; Latham, I. J.; Le Gallou, R.; Lemoine-Goumard, M.; Lemière, A.; Leroy, N.; Lohse, T.; Marcowith, A.; Masterson, C.; McComb, T. J. L.; de Naurois, M.; Nolan, S. J.; Noutsos, A.; Orford, K. J.; Osborne, J. L.; Ouchrif, M.; Panter, M.; Pelletier, G.; Pita, S.; Fuchs, Y.; Pühlhofer, G.; Punch, M.; Raubenheimer, B. C.; Raue, M.; Raux, J.; Rayner, S. M.; Martin, J.M.; Reimer, A.; Reimer, O.; Ripken, J.; Terrier, R.; Rob, L.; Rolland, L.; Rowell, G.; Sahakian, V.; Saugé, L.; Schlenker, S.; Schlickeiser, R.; Schuster, C.; Schwanke, U.; Siewert, M.; Sol, H.; Steenkamp, R.; Stegmann, C.; Tavernet, J.-P-; Théoret, C. G.; Tluczykont, M.; Venter, C.; Vasileiadis, G.; Vincent, P.; Völk, H. J.; Wagner, S. J.; Martineau-Huynh, O.; Spangler, D.
Language:English
Research Context:H.E.S.S.
Date of Publication (YYYY-MM-DD):2006-04-20
Title of Journal:Nature
Volume:440
Issue / Number:7087
Start Page:1018
End Page:1021
Copyright:Nature
Review Status:Peer-review
Audience:Experts Only
Abstract / Description: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 light1. An alternative approach2,3,4,5 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 photons6. Here we report the discovery of gamma-ray emission from the blazars7 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 galaxies8. 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 formed9. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought.
Free Keywords:Gamma rays: observations
H.E.S.S.
External Publication Status:published
Document Type:Article
Affiliations:MPI für Kernphysik/Group of W. Hofmann/High Energy Astrophysics (F. Aharonian)
MPI für Kernphysik/Group of W. Hofmann/Experimental High-Energy Astrophysics (M. Panter, G. Hermann)
External Affiliations:Yerevan Physics Institute, 2 Alikhanian Brothers Street, 375036 Yerevan, Armenia.
Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK.
Centre d'Etude Spatiale des Rayonnements, CNRS/UPS, 9 av. du Colonel Roche, BP 4346, F-31029 Toulouse Cedex 4, France.
Institut für Experimentalphysik, Universität Hamburg, Luruper Chaussee 149, D-22761 Hamburg, Germany.
APC, UMR 7164 du CNRS, 11 Place Marcelin Berthelot, F-75231 Paris Cedex 05, France.
Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany.
Laboratoire Univers et Théories (LUTH), UMR 8102 du CNRS, Observatoire de Paris, Section de Meudon, F-92195 Meudon Cedex, France.
Laboratoire de Physique Théorique et Astroparticules, IN2P3/CNRS, Université Montpellier II, CC 70, Place Eugène Bataillon, F-34095 Montpellier Cedex 5, France.
Laboratoire Leprince-Ringuet, IN2P3/CNRS, Ecole Polytechnique, F-91128 Palaiseau, France.
Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2, Ireland.
Landessternwarte, Königstuhl, D-69117 Heidelberg, Germany.
Laboratoire d'Astrophysique de Grenoble, INSU/CNRS, Université Joseph Fourier, BP 53, F-38041 Grenoble Cedex 9, France.
DAPNIA/DSM/CEA, CE Saclay, F-91191 Gif-sur-Yvette, France.
Unit for Space Physics, North-West University, Potchefstroom 2520, South Africa.
Laboratoire de Physique Nucléaire et de Hautes Energies, IN2P3/CNRS, Universités Paris VI & VII, 4 Place Jussieu, F-75252 Paris Cedex 05, France.
Institut für Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum, Germany.
Institute of Particle and Nuclear Physics (IPNP), Charles University, V Holesovickach 2, 180 00 Prague 8, Czech Republic.
University of Namibia, Private Bag 13301, Windhoek, Namibia.
Identifiers:DOI:10.1038/nature04680
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