1991 Fiscal Year Final Research Report Summary
A Study of Neutral Particles from Cygnus X-3 above 10^<18>eV
| Project/Area Number |
02452021
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Institute for Cosmic Ray Research, University of Tokyo. |
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Principal Investigator |
TESHIMA Masahiro ICRR,Univ.of Tokyo ; Assoc.Professor, 宇宙線研究所, 助教授 (40197778)
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| Co-Investigator(Kenkyū-buntansha) |
HAYASHIDA Naoaki ICRR,Univ.of Tokyo ; Assistant, 宇宙線研究所, 助手 (50114616)
NAGANO Motohiko ICRR,Univ.of Tokyo ; Professor, 宇宙線研究所, 教授 (00013384)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Cosmic Ray / Cygnus X-3 / Gamma Ray / Neutral Particles / Air Shower |
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| Research Abstract |
The Akeno Giant Air Shower Array (AGASA), covering 100km^2 area, has been in operation since 1990. This new array has accumulated more events than the number observed with the 20km^2 which has been in operation for over 5 years. Analysis of the data up through Nov 1991 to lood for excess in the direction of Cygnus X-3 shows 1 month that has a 4sigma excess number of events, occuring right after the strong radio burst of Jan 1991. No other time period shows a significant excess. The cummulative data set of AGASA shows a 2.5sigma excess in the direction of Cygnus X-3, still lower than necessary to make a strong claim for source emission. More data will be needed to clarify the characteristics of neutral emission from Cygnus X-3.
We have improved the experiment in several ways to enhance sensitivity to neutral source emission. Installation of a detector calibration system gives us better rise time and gain certainty. The threshold energy of detectable showers has been decreased down to 10^<17>eV and the resulting trigger rate is lower (-0.1Hz). A new workstation in the central laboratory collects and writes the data to Magnetic Optical disks. These on-line systems are monitored and controlled from our Institute in Tokyo using telecommunications. Improvements have been made on analysis which have been used to measure the directional excess, test for periodicity, and search for bursts.
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