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MAGIC discovers pulsed VHE gamma ray emission above 25 GeV from the Crab pulsar

ATel #1491; Masahiro Teshima, Spokesperson for the MAGIC collaboration
on 28 Apr 2008; 16:01 UT
Credential Certification: Masahiro Teshima (mteshima@mppmu.mpg.de)

Subjects: Gamma Ray, >GeV, Pulsar

The MAGIC collaboration reports the detection of the Crab pulsar in very high energy gamma rays, using the 17m diameter MAGIC Cherenkov telescope on La Palma (27.8 N, 17.8 W, 2200 m asl). We observed the Crab pulsar from October 2007 until February 2008 for a total of 40 hours. For the analysis 22 hours of data at optimal weather conditions and small zenith angles were selected. The observation took place after installation of a new trigger system which lowered the threshold from 50-60GeV down to 25 GeV. The analysis reveals a pulse profile that shows a clear signal at a 6.4 sigma confidence level coinciding with an optical signal concurrently recorded by a special photosensor in the camera center. We observed about 8500 pulsed gamma ray events in total. Two peaks in the phaseogram are found, corresponding to the main pulse and the interpulse. Both are clearly visible and are in phase with the emission at lower energies, including gamma-ray energies above 100MeV as observed by EGRET.