Volume 565, May 2014
|Number of page(s)||5|
|Published online||29 May 2014|
Detection of bridge emission above 50 GeV from the Crab pulsar with the MAGIC telescopes⋆
IFAE, Campus UAB,
2 Università di Udine, and INFN Trieste, 33100 Udine, Italy
3 INAF National Institute for Astrophysics, 00136 Rome, Italy
4 Università di Siena, and INFN Pisa, 53100 Siena, Italy
5 Croatian MAGIC Consortium, Rudjer Boskovic Institute, University of Rijeka and University of Split, 10000 Zagreb, Croatia
6 Max-Planck-Institut für Physik, 80805 München, Germany
7 Universidad Complutense, 28040 Madrid, Spain
8 Inst. de Astrofísica de Canarias, 38200, La Laguna, Tenerife, Spain
9 University of Łódź, 90236 Lodz, Poland
10 Deutsches Elektronen-Synchrotron (DESY), 15738 Zeuthen, Germany
11 ETH Zurich, 8093 Zurich, Switzerland
12 Universität Würzburg, 97074 Würzburg, Germany
13 Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas, 28040 Madrid, Spain
14 Technische Universität Dortmund, 44221 Dortmund, Germany
15 Università di Padova and INFN, 35131 Padova, Italy
16 Università dell’Insubria and INFN Milano Bicocca, Como, 22100 Como, Italy
17 Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain
18 Institut de Ciències de l’Espai (IEEC-CSIC), 08193 Bellaterra, Spain
19 Japanese MAGIC Consortium, Division of Physics and Astronomy, Kyoto University, 606-8501 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, 900147 Oulu, Finland
22 Inst. for Nucl. Research and Nucl. Energy, 1784 Sofia, Bulgaria
23 Universitat de Barcelona, ICC, IEEC-UB, 08028 Barcelona, Spain
24 Università di Pisa, and INFN Pisa, 56126 Pisa, Italy
25 ICREA and Institut de Ciències de l’Espai (IEEC-CSIC), 08193 Bellaterra, Spain
26 Now at: NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA and Department of Physics and Department of Astronomy, University of Maryland, College Park, MD 20742, USA
27 Now at: École polytechnique fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
28 Now at: Finnish Centre for Astronomy with ESO (FINCA), Turku, Finland
29 Also at INAF-Trieste, Italy
30 Now at: Stockholm University, Oskar Klein Centre for Cosmoparticle Physics, 106 91 Stockholm, Sweden
Accepted: 24 April 2014
Context. The Crab pulsar is the only astronomical pulsed source detected at very high energy (VHE, E > 100 GeV) gamma rays. The emission mechanism of VHE pulsation is not yet fully understood, although several theoretical models have been proposed.
Aims. In order to test new models, we measured the light curve and the spectra of the Crab pulsar with high precision by means of deep observations.
Methods. We analyzed 135 h of selected MAGIC data taken between 2009 and 2013 in stereoscopic mode. In order to discuss the spectral shape in connection with lower energies, 5.5 years of Fermi-LAT data were also analyzed.
Results. The known two pulses per period were detected with a significance of 8.0σ and 12.6σ. In addition, significant emission was found between the two pulses with 6.2σ.
Conclusions. We discovered the bridge emission above 50 GeV between the two main pulses. This emission can not be explained with the existing theories. These data can be used for testing new theoretical models.
Key words: gamma rays: stars / pulsars: individual: Crab pulsar / stars: neutron
The lightcurve data of Fig. 1 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/L12
© ESO, 2014
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