Teraelectronvolt pulsed emission from the Crab Pulsar detected by MAGIC

¹ Università di Udine, and INFN Trieste, 33100 Udine, Italy
² INAF National Institute for Astrophysics, 00136 Rome, Italy
³ Università di Siena, and INFN Pisa, 53100 Siena, Italy
⁴ Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, 10000 Zagreb, Croatia
⁵ Max-Planck-Institut für Physik, 80805 München, Germany
⁶ Universidad Complutense, 28040 Madrid, Spain
e-mail: dfidalgo@gae.ucm.es
⁷ Inst. de Astrofísica de Canarias, 38200 La Laguna, Tenerife, Spain
⁸ University of Łódź, 90236 Lodz, Poland
⁹ Deutsches Elektronen-Synchrotron (DESY), 15738 Zeuthen, Germany
¹⁰ ETH Zurich, 8093 Zurich, Switzerland
¹¹ IFAE, Campus UAB, 08193 Bellaterra, Spain
¹² Universität Würzburg, 97074 Würzburg, Germany
¹³ Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, 28040 Madrid, Spain
¹⁴ Institute of Space Sciences (CSIC-IEEC), 08193 Barcelona, Spain
e-mail: wilhelmi@aliga.ieec.uab.es
¹⁵ Università di Padova and INFN, 35131 Padova, Italy
¹⁶ Technische Universität Dortmund, 44221 Dortmund, Germany
¹⁷ Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
¹⁸ Universitat de Barcelona, ICC, IEEC-UB, 08028 Barcelona, Spain
e-mail: robertazanin@gmail.com, dgalindo@am.ub.es
¹⁹ Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, Kyoto, Japan
²⁰ Academia Sinica, Institute of Astronomy and Astrophysics (ASIAA), PO Box 23-141, 10617 Taipei, Taiwan
²¹ Finnish MAGIC Consortium, Tuorla Observatory, University of Turku and Department of Physics, University of Oulu, 90014 Oulu, Finland
²² Inst. for Nucl. Research and Nucl. Energy, 1784 Sofia, Bulgaria
²³ Università di Pisa, and INFN Pisa, 56126 Pisa, Italy
²⁴ ICREA and Institute of Space Sciences, 08193 Barcelona, Spain
²⁵ Università dell’Insubria and INFN Milano Bicocca, Como, 22100 Como, Italy
²⁶ Now at Centro Brasileiro de Pesquisas Físicas (CBPF\MCTI), R. Dr. Xavier Sigaud, 150 – Urca, 22290-180 Rio de Janeiro – RJ, Brazil
²⁷ Now at NASA Goddard Space Flight Center, Greenbelt, MD 20771, and Department of Physics and Department of Astronomy, University of Maryland, College Park, MD 20742, USA
²⁸ Now at École polytechnique fédérale de Lausanne (EPFL), Lausanne, Switzerland
²⁹ Now at Finnish Centre for Astronomy with ESO (FINCA), Turku, Finland
³⁰ Also at INAF-Trieste, Italy
³¹ Also at ISDC – Science Data Center for Astrophysics, 1290, Versoix, Geneva, Switzerland

Received: 29 June 2015
Accepted: 20 October 2015

Abstract

Aims. We investigate the extension of the very high-energy spectral tail of the Crab Pulsar at energies above 400 GeV.

Methods. We analyzed ~320 h of good-quality Crab data obtained with the MAGIC telescope from February 2007 to April 2014.

Results. We report the most energetic pulsed emission ever detected from the Crab Pulsar reaching up to 1.5 TeV. The pulse profile shows two narrow peaks synchronized with those measured in the GeV energy range. The spectra of the two peaks follow two different power-law functions from 70 GeV up to 1.5 TeV and connect smoothly with the spectra measured above 10 GeV by the Large Area Telescope (LAT) on board the Fermi satellite. When making a joint fit of the LAT and MAGIC data above 10 GeV the photon indices of the spectra differ by 0.5 ± 0.1.

Conclusions. Using data from the MAGIC telescopes we measured the most energetic pulsed photons from a pulsar to date. Such TeV pulsed photons require a parent population of electrons with a Lorentz factor of at least 5 × 10⁶. These results strongly suggest IC scattering off low-energy photons as the emission mechanism and a gamma-ray production region in the vicinity of the light cylinder.