1991 Fiscal Year Final Research Report Summary
Search for High Energy Gamma-ray Sources in the Southern Sky
| Project/Area Number |
02044079
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Department of Physics, Kyoto University |
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Principal Investigator |
SATO Humitaka Department of Physics, Kyoto University, 理学部, 教授 (90025370)
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| Co-Investigator(Kenkyū-buntansha) |
STOREY J. R. Department of Physics, University of Auckland, Professor
SAKATA Michinori Department of Physics, Konan University, 理学部, 教授 (60068111)
YOCK P. C. M. Department of Physics, University of Auckland, Professor
FUJII Zenjiro Cosmic Ray Section, STE Laboratory, Nagoya University, 太陽地球環境研究所, 助手 (10022724)
MURAKI Yasushi Cosmic Ray Section, STE Laboratory, Nagoya University, 太陽地球環境研究所, 教授 (70013430)
TESHIMA Masahiro Institute for Cosmic Ray Research , Tokyo University, 助教授 (40197778)
FUJII Hirofumi KEK, 助教授 (60013439)
KABE Seiji KEK, 助教授 (10044786)
MATSUBARA Yutaka Department of Physics, Tokyo Institute of Technology, 理学部, 助手 (80202323)
HAYASHIDA Naoaki Institute for Cosmic Ray Research, Tokyo University, 宇宙線研究所, 助手 (50114616)
KIFUNE Tadashi Institute for Cosmic Ray Research, Tokyo University, 宇宙線研究所, 助教授 (40011621)
NAGANO Motohiko Institute for Cosmic Ray Research, Tokyo University, 宇宙線研究所, 教授 (00013384)
MASAIKE Akira Department of Physics, Kyoto University, 理学部, 教授 (40022587)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Supernova / SN1987A / Ultra High Energy gamma-ray / Counter Array / Neutron Star / Magellanic Cloud / Ejecta |
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| Research Abstract |
The supernova 1987A in the Large Magellanic Cloud has provided the first opportunity to study the emission of particles and electromagnetic radiation from a young supernova. A rapidly rotating, magnetized neutron star at the center of the expanding ejecta may be a powerful source of ultra high-energy (UHE) cosmic rays. H. Sato has pointed out that high energy gamma-rays may be produced from the decay pions generated by the collisions of hadrons accelerated by the neutron star with supernova ejecta. We installed gamma-ray detectors at the Black Birch in New Zealand (1640 m above sea level, 41ﾟ45'S, 173ﾟ47'E). The counter array consists of 76 scintillation detectors. The observations started on 13 October 1987. An upper limit on tile flux of UHE gamma-rays from SN1987A (>100 TeV) was obtained to be 4X10^<-14> cm^<-2> sec^<-1> from the data of 1987-1991. gamma-rays above 3 TeV emitted by SN1987A have been searched for using three, Cerenkov mirrors and data give an upper bound on the flux of 5X10^<-12> cm^<-2> sec^<-1>. Data on January 14 and 15 1988 were found to have excess counts corresponding to a flux of (1.9<plus-minus>0.5)X10^<-11> cm^<-2> sec^<-1>. The observed time of the excess coincides with the time of X-ray flare detected by the Ginga Satellite.
Recently, we have searched for UHE gamma-ray from Southern objects including Cen A, Vela X-1, Cen X-3, Cir X-1 and also several objects in the Magellanic Clouds. None of these sources shows significant excess events. The observation is still being carried out.
The moon was used to measure the angular resolution of the detector through its shadowing effect. The density of the events at the center of the moon has been found to be lower than event density near direction of the moon.
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