Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Research Institution||Okayama University|
KANEKO Tatunosuke Professor, Faculty of Science, Okayama University, 理学部, 教授 (10032799)
金子 逹之助(1990) 岡山大学, 理学部, 教授
ポマ イサック サン, アンドレス大学・物理学研究所(ボリウ゛ィア国), 助教授
NISHI Katsuo Chief Engineer, Technology Division, the Institute of Physical and Chemical Rese, 研究基盤技術部・極限計測技術室, 室長
TOYADA Yoshio Professor Emeritus, Faculty of Science, Kobe University, 名誉教授
KAKIMOTO Fumio Associate Professor, Faculty of Science, Tokyo Institute of Technology, 理学部, 助教授 (00092544)
YOSHII Hisashi Associate Professor, Faculty of General Education, Ehime UniversityY, 教養部, 助教授 (00036360)
POMA Isac Associate Professor, Instituto de Investigaciones Fisicas, Universidad Mayor de
|Project Period (FY)
1988 – 1990
Completed(Fiscal Year 1990)
|Budget Amount *help
¥9,000,000 (Direct Cost : ¥9,000,000)
Fiscal Year 1990 : ¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1989 : ¥3,000,000 (Direct Cost : ¥3,000,000)
Fiscal Year 1988 : ¥3,000,000 (Direct Cost : ¥3,000,000)
|Keywords||Air showers / Primary gamma-rays / Gamma-ray astronomy|
The Bolivian Air Shower Joint Experiment group has operated two air shower arrays in order to search for point and diffuse gamma-ray sources at Mt. Chacaltaya (5200m, 68.1^oW, 16.3^oS) in Bolivia. The purpose of the study is to make clear the problem on Cosmic Ray Origin.
After three years observations, the observed results are as follows :
1. UHE gamma-ray emission from X-ray eclipsing binaries (Vela X-1, Cen X-3, X1822-371), Vela pulsar, a radio galaxy (Cen A), a flaring X-ray source (SS433) and the center of Galaxy are examined by comparing the amount of onーsource low muon events with that of background cosmic rays estimated from off-source low muon events. The results at present show no significant evidence of UHE gamma-ray emission from the above mentioned objects. The 95% C. L. upper limits of the emission are obtained.
2. Observation for UHE gamma-ray emission from notable SN1987A has been carried out since January 1988. The DC excess for daily and weekly variation was analyzed. There is no significant evidence concerning the arrival of UHE gamma-rays from SN1987A. No information is also presented any group in Australia, New Zealand, the Republic of South Africa and the South Pole. The upper limit on the flux of gamma-rays with energies above 100 TeV is estimated as being 2.4 x 10^<-13>cm^<-2>s^<-1> (95% C. L.).
3. Diffuse gamma-rays with energies above 100 TeV is analyzed using selected shower with low content of muons. Our interesting region is that of 180^ﾟ - 210^ﾟ in right ascension (R. A.) and 0^ﾟ - -40^ﾟ in declination (delta) from the report in 1985. However, it wasn't found the excess in a such region. In place of this region, new one of 135^ﾟ- 150^ﾟ in R. A. and -20^ﾟ --40^ﾟ in delta presents 4.6sigma (sigma, standard deviation) of the excess. Li-Ma test for small number events, however, shows 3.2sigma. So, it seems statistically no significant.