A Lower Limit to the Magnetic Field in the Crab Nebula from Cosmic γ-Ray Experiments at 1011 eV [chapter]

G. G. Fazio, H. F. Helmken, G. H. Rieke, T. C. Weekes
1970 Non-Solar X- and Gamma-Ray Astronomy  
The 10-m optical reflector at Mt. Hopkins, Arizona, has been used to search for cosmic y-rays by the detection of atmospheric Cerenkov radiation from energetic particle showers. Approxi mately 100 drift scans of the Crab Nebula during 1968-69 have yielded no positive evidence of a y-ray flux. The upper limit to the flux at 1.7 x 10 11 eV is 2.0 x 10 10 photons/cm 2 sec. Assuming y-rays of this energy are produced by Compton scattering, a lower limit on the average magnetic field in the Crab
more » ... eld in the Crab Nebula is 1.5 x 10 -4 gauss. This experiment also verifies previous evidence that the high-energy electrons in the Crab Nebula are not the secondary products of high-energy proton interactions but must have been accelerated from lower energies. L. Gratton (ed.), Non-Solar X-and Gamma-Ray Astronomy, 250-256. All Rights Reserved
doi:10.1007/978-94-010-3311-4_42 fatcat:lv7r4clvjfeobgwk7fstdokmrq