Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?

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The MAGIC Collaboration: J. Albert,¹ E. Aliu,² H. Anderhub,³ L. A. Antonelli,⁴ P. Antoranz,⁵ M. Backes,⁶ C. Baixeras,⁷ J. A. Barrio,⁵ H. Bartko,⁸ D. Bastieri,⁹ J. K. Becker,⁶ W. Bednarek,¹⁰ K. Berger,¹ E. Bernardini,¹¹ C. Bigongiari,⁹ A. Biland,³ R. K. Bock,^8,9* G. Bonnoli,¹² P. Bordas,¹³ V. Bosch-Ramon,¹³ T. Bretz,¹ I. Britvitch,³ M. Camara,⁵ E. Carmona,⁸ A. Chilingarian,¹⁴ S. Commichau,³ J. L. Contreras,⁵ J. Cortina,² M. T. Costado,^15,16 S. Covino,⁴ V. Curtef,⁶ F. Dazzi,⁹ A. De Angelis,¹⁷ E. De Cea del Pozo,¹⁸ R. de los Reyes,⁵ B. De Lotto,¹⁷ M. De Maria,¹⁷ F. De Sabata,¹⁷ C. Delgado Mendez,¹⁵ A. Dominguez,¹⁹ D. Dorner,¹ M. Doro,⁹ M. Errando,² M. Fagiolini,¹² D. Ferenc,²⁰ E. Fernández,² R. Firpo,² M. V. Fonseca,⁵ L. Font,⁷ N. Galante,⁸ R. J. García López,^15,16 M. Garczarczyk,⁸ M. Gaug,¹⁵ F. Goebel,⁸ M. Hayashida,⁸ A. Herrero,^15,16 D. Höhne,¹ J. Hose,⁸ C. C. Hsu,⁸ S. Huber,¹ T. Jogler,⁸ T. M. Kneiske,⁶ D. Kranich,³ A. La Barbera,⁴ A. Laille,²⁰ E. Leonardo,¹² E. Lindfors,²¹ S. Lombardi,⁹ F. Longo,¹⁷ M. López,⁹ E. Lorenz,^3,8 P. Majumdar,⁸ G. Maneva,²² N. Mankuzhiyil,¹⁷ K. Mannheim,¹ L. Maraschi,⁴ M. Mariotti,⁹ M. Martínez,² D. Mazin,² M. Meucci,¹² M. Meyer,¹ J. M. Miranda,⁵ R. Mirzoyan,⁸ S. Mizobuchi,⁸ M. Moles,¹⁹ A. Moralejo,² D. Nieto,⁵ K. Nilsson,²¹ J. Ninkovic,⁸ N. Otte,^8,23 I. Oya,⁵ M. Panniello,¹⁵ R. Paoletti,¹² J. M. Paredes,¹³ M. Pasanen,²¹ D. Pascoli,⁹ F. Pauss,³ R. G. Pegna,¹² M. A. Perez-Torres,¹⁹ M. Persic,^17,24 L. Peruzzo,⁹ A. Piccioli,¹² F. Prada,¹⁹ E. Prandini,⁹ N. Puchades,² A. Raymers,¹⁴ W. Rhode,⁶ M. Ribó,¹³ J. Rico,^25,2 M. Rissi,³ A. Robert,⁷ S. Rügamer,¹ A. Saggion,⁹ T. Y. Saito,⁸ M. Salvati,⁴ M. Sanchez-Conde,¹⁹ P. Sartori,⁹ K. Satalecka,¹¹ V. Scalzotto,⁹ V. Scapin,¹⁷ R. Schmitt,¹ T. Schweizer,⁸ M. Shayduk,^8,23 K. Shinozaki,⁸ S. N. Shore,²⁶ N. Sidro,² A. Sierpowska-Bartosik,¹⁸ A. Sillanpää,²¹ D. Sobczynska,¹⁰ F. Spanier,¹ A. Stamerra,¹² L. S. Stark,³ L. Takalo,²¹ F. Tavecchio,⁴ P. Temnikov,²² D. Tescaro,² M. Teshima,⁸ M. Tluczykont,¹¹ D. F. Torres,^25,18 N. Turini,¹² H. Vankov,²² A. Venturini,⁹ V. Vitale,¹⁷ R. M. Wagner,⁸ W. Wittek,⁸ V. Zabalza,¹³ F. Zandanel,¹⁹ R. Zanin,² J. Zapatero⁷

The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar Radio Source (in short: radio quasar) 3C 279, at a distance of more than 5 billion light-years (a redshift of 0.536). No quasar has been observed previously in very-high-energy gamma radiation, and this is also the most distant object detected emitting gamma rays above 50 gigaelectron volts. Because high-energy gamma rays may be stopped by interacting with the diffuse background light in the universe, the observations by MAGIC imply a low amount for such light, consistent with that known from galaxy counts.

¹ Universität Würzburg, D-97074 Würzburg, Germany.
² Institut de Física d'Altes Energies, Edifici Cn., Campus UAB, E-08193 Bellaterra, Spain.
³ ETH Zurich, CH-8093 Zurich, Switzerland.
⁴ Istituto Nazionale di Astrofisica (INAF) National Institute for Astrophysics, I-00136 Rome, Italy.
⁵ Universidad Complutense, E-28040 Madrid, Spain.
⁶ Technische Universität Dortmund, D-44221 Dortmund, Germany.
⁷ Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain.
⁸ Max-Planck-Institut für Physik, D-80805 München, Germany.
⁹ Università di Padova and INFN, I-35131 Padova, Italy.
¹⁰ University of ód, PL-90236 Lodz, Poland.
¹¹ DESY Deutsches Elektronen-Synchrotron D-15738 Zeuthen, Germany.
¹² Università di Siena, and INFN Pisa, I-53100 Siena, Italy.
¹³ Universitat de Barcelona Institut de Ciencias del Cosmos–Institut d'Estudis Especials de Catalunya (IEEC), E-08028 Barcelona, Spain.
¹⁴ Yerevan Physics Institute, AM-375036 Yerevan, Armenia.
¹⁵ Instituto de Astrofisica de Canarias, E-38200, La Laguna, Tenerife, Spain.
¹⁶ Departamento de Astrofisica, Universidad, E-38206 La Laguna, Tenerife, Spain.
¹⁷ Università di Udine, and INFN Trieste, I-33100 Udine, Italy.
¹⁸ Institut de Cienciès de l'Espai [IEEC-Consejo Superior de Investigaciones Cíentificas (CSIC)], E-08193 Bellaterra, Spain.
¹⁹ Inst. de Astrofisica de Andalucia (CSIC), E-18080 Granada, Spain.
²⁰ University of California, Davis, CA 95616–8677, USA.
²¹ Tuorla Observatory, Turku University, FI-21500 Piikkiö, Finland.
²² Institute for Nuclear Research and Nuclear Energy, BG-1784 Sofia, Bulgaria.
²³ Humboldt-Universität zu Berlin, D-12489 Berlin, Germany.
²⁴ INAF/Osservatorio Astronomico and INFN, I-34143 Trieste, Italy.
²⁵ Institució Catalana de Recerca i Estudis Avancats, E-08010 Barcelona, Spain.
²⁶ Università di Pisa, and INFN Pisa, I-56126 Pisa, Italy.
* Corresponding author, rkbock@gmail.com