Three-year search for periodic gamma-ray emission in the 1011-1012 eV energy region from NP 0532

view Abstract Citations (14) References (10) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Three-Year Search for Periodic Gamma-Ray Emission in the 1011-1011 EV Energy Region from NP 0532 Helmken, H. F. ; Fazio, G. G. ; O'Mongain, E. ; Weekes, T. C. Abstract The 10-m optical reflector at the Mount Hopkins Observatory, Arizona, was used in a search for periodic y-ray emission from NP 0532 by detecting the Cerenkov light generated in the atmosphere by energetic-particle showers. Detection of a continuous flux of 10 -10 eV v-rays from the Crab Nebula was previously reported. Arrival times of air showers for over 200 hours of these observations were recorded to an absolute precision of 200 s. An analysis of the recorded data using the optical pulsar period and phase revealed no statistical excess at the main pulse or interpulse. A typical upper limit to the flux above 2 x 1011 eV, for a 3.3-ms pulse width and E 1.1 spectrum, is 2.3 x 10-11 keV cm - 2 1 keV - 1 This upper limit indicates that a break must occur in the pulsar spectrum between 10 and 1011 eV. Subject headings: gamma rays - pulsars Publication: The Astrophysical Journal Pub Date: August 1973 DOI: 10.1086/152323 Bibcode: 1973ApJ...184..245H full text sources ADS |