Gamma Ray Study on High Energy Phenomena of Celestial objects

我们在1995年以前的研究使我们能够（i）在1992年康普顿伽马射线卫星发射的第二年开始操作我们的3.8米成像切伦科夫光望远镜进行伽马射线探测，（ii）通过使用最高角分辨率的相机来证明高分辨率相机的强大效率，直到1996年，（iii）从南半球观测蟹状星云的数据显示在大天顶角观测探测10-100 TeV区域的甚高能量伽马射线的能力。基于这些技术的发展，我们在PSR B 1706- 44中发现了1 TeV的伽马射线。1997年获得的结果是：（1）从距离船帆座脉冲星位置约0.1的区域发射出甚高能伽马射线（-1 TeV），这与脉冲星诞生的位置一致。通过比较观测到的伽马射线强度与X射线强度，估计发射区的磁场弱至4 μ G。(2)来自蟹状星云的伽马射线的能谱被发现至少持续到50 TeV，这是有史以来探测到的最高能量的伽马射线。(3)从超新星遗迹SN 1006中探测到了非常高能量的伽马射线。结果表明，伽马射线是由大约100 TeV的电子产生的，这为这些电子在超新星遗迹的东北边缘受到冲击加速提供了直接证据。(4)从伽马射线脉冲星PSR B 1509-58中获得了1 TeV伽马射线的线索。去年的数据（阈值能量较高）没有显示信号，表明能量谱陡峭。(6)1997财政年度还观测到其他物体，如伽马射线爆发、银河系中心Sgr A^**>、几个活动星系核、身份不明的EGRET源和近距离X射线双星。数据正在分析中。

Our preceding study before the year 1995 has enabled us (i) to commence operation of our 3.8m telescope of imaging Cerenkov lights for gamma ray detection, in 1992 the next year of the launching of Compton gamma ray satellite, (ii) to prove the powerful efficiency of high resolution camera by using the camera of the highest angular resolution until 1996, (iii) to show the ability of observations at large zenith angles for detecting very high energy gamma rays in 10-100 TeV region from the data observing the Crab from the southern hemisphere. Based on these technical development, we have discovered 1 TeV gamma rays from PSR B 1706-44.The results obtained in 1997 are : (1) Very high energy gamma rays (-1TeV) are emitted from a region displaced from the Vela pulsar position by about 0.1ﾟ, which is consistent with the position where the pulsar was born. By comparing the observed gamma ray intensity with X-ray's, the magnetic field in the emission region is estimated as weak as 4muG.(2) The energy spectrum of gamma rays from the Crab nebula is found to continue at least up to 50 TeV,which are the gamma rays of the highest energy that have ever been detected.(3) Very high energy gamma rays has been detected from a supernova remnant SN1006. The result demonstrates that the gamma rays are produced by about 100 TeV electrons, providing a direct evidence that these electrons are shock-acceletated in the north-east rim of the supernova remnant. (4) A hint of 1 TeV gamma rays has been obtained from a gamma ray pulsar PSR B 1509-58. The data in the last year (of a higher threshold energy) shows no indication of signal, suggesting a steep energy spectrum. (6) Other objects, such as a gamma ray burst, the Galactic center Sgr A^<**>, several active galactic nuclei, unidentified EGRET sources and close X-ray binaries, are observed in the 1997 fiscal year. The data are now under analysis.