Observation of Celestial Gamma-ray Objects with Imaging Cerenkov Telescope

对极高能量伽马射线的观测是天文学的最新前沿。目前的研究开始的目的是建造一个望远镜，用于探测1000 GeV= 1 TeV的高能伽马射线，然后从各种天体中添加更多的观测数据。(1)我们把一个3.8米的抛物面望远镜运到了澳大利亚。通过安装一个由220个光电倍增管组成的具有目前最高分辨率的照相机，并通过增加一个电子电路系统和一台计算机，使切伦科夫成像望远镜投入使用。该装置具有-0.1的角分辨率，能够将宇宙射线背景降低约100倍。观测的目标是年轻的超新星、超新星遗迹和活动星系核，已知这些星系核会发射GeV能量的伽马射线。(2)从PSR 1706 -44中检测到TeV γ射线信号。这是第一个来自这个物体的TeV伽马射线的迹象，使其成为仅次于螃蟹的第二个银河系TeV伽马射线发射器。(3)从蟹状星云脉冲星中也发现了6 TeV的γ射线的证据，这使我们能够将望远镜的特性与美国维普莱天文台的特性进行比较，并提供有关该物体的新数据。有了这些结果，我们就可以朝着建立极高能伽马射线天文学的最终目标迈出一步。观测仍在进行中，我们期待着从许多其他天体获得更多的观测数据。

Observation of very high energy gamma-rays is the last frontier in astronomy. The present research was commenced with a purpose to construct a telescope for detecting energetic gamma-rays at 1000 GeV=1TeV,and then to add more observational data in this energy region from various celestial objects. (1) We transported a 3.8 m parabolic telescope to Australia. By setting a camera of 220 photomultiplier tubes which has the current highest resolution and by adding a system of electronics circuits and a computer, an imaging Cerenkov telescope was made into operation. The apparatus has an angular resolution of -0.1ﾟ with a capability of reducing cosmic ray background by a factor of about 100. Observation has been done aiming at young pulsars, supernova remnants and active galactic nuclei which are known to emit gamma-rays at GeV energies. (2) A signal of TeV gamma-rays was detected from PSR1706-44. It is the first indication of TeV gamma-rays from this object, making it the second Galactic TeV gamma-ray emitter next to the Crab. (3) An evidence of gamma-rays of 6 TeV was found also from the Crab pulsar/nebula, which enables us to calibrate the characteristics of the telescope in comparison with the one of the Whipple Observatory in USA,as well as to provide with new data on this object. With these results, we could start a step toward our final goal of establishing very high energy gamma-ray astronomy. The observation is still under way, and we expect more observational data from many other objects.