Phase-resolved energy spectra of the Crab pulsar in the range of 50-400 GeV measured with the MAGIC telescopes

© ESO. We would like to thank the Instituto de Astrofisica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the Marie Curie programme, the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, grant DO02-353 of the Bulgarian NSF, grant 127740 of the Academy of Finland, the YIP of the Helmholtz Gemeinschaft, the DFG Cluster of Excellence "Origin and Structure of the Universe", the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, the Polish MNiSzW grant 745/N-HESS-MAGIC/2010/0 and the Formosa Program between the National Science Council in Taiwan and the Consejo Superior de Investigaciones Cientificas in Spain administered through the grant number NSC100-2923-M-007-001-MY3.
We use 73 h of stereoscopic data taken with the MAGIC telescopes to investigate the very high-energy (VHE) gamma-ray emission of the Crab pulsar. Our data show a highly significant pulsed signal in the energy range from 50 to 400 GeV in both the main pulse (P1) and the interpulse (P2) phase regions. We provide the widest spectra to date of the VHE components of both peaks, and these spectra extend to the energy range of satellite-borne observatories. The good resolution and background rejection of the stereoscopic MAGIC system allows us to cross-check the correctness of each spectral point of the pulsar by comparison with the corresponding (strong and well-known) Crab nebula flux. The spectra of both P1 and P2 are compatible with power laws with photon indices of 4.0 +/- 0.8 (P1) and 3.42 +/- 0.26 (P2), respectively, and the ratio P1/P2 between the photon counts of the two pulses is 0.54 +/- 0.12. The VHE emission can be understood as an additional component produced by the inverse Compton scattering of secondary and tertiary e(+/-) pairs on IR-UV photons.
German BMBF
German MPG
Italian INFN
Swiss National Fund SNF
Spanish MICINN
Spanish Consolider-Ingenio programme
Bulgarian NSF
Academy of Finland
YIP of the Helmholtz Gemeinschaft
DFG
DFG Collaborative Research Centers
Polish MNiSzW
National Science Council in Taiwan
Consejo Superior de Investigaciones Científicas in Spain
Depto. de Estructura de la Materia, Física Térmica y Electrónica
Fac. de Ciencias Físicas
TRUE
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