用羊八井加密阵列数据寻找3TeV能区γ暴的初步结果

A Primary Result to Search for 3 TeV γ-ray Bursts by using Data of Tibet HD Air Shower Array

报道了用 1 996年 1 0月完成的羊八井 EAS加密阵列探测器 ( Tibet 和 HD)于 1 997- 1 998年进行的全天区观测数据 ,对 3Te Vγ暴进行寻找的结果 .发现了一批显著性明显超过 3σ、少数显著性超过

A search for γ ray bursts at 3 TeV energy region was done by using the data of Tibet HD air shower array, which was obtained in the period of Febuary 1997-June 1998. About 2.5×10 9 EAS events were analysed to search for the shower clusters appearing in a fixed time intervial and small sky bin. An equal zenith angle method is used to estimate the background and three different time intervals(Δ t =1, 10, 100 s) were adopted in the research. A part of clusters show excess over the background and some significances are greater than 3 σ obviously. Although a few clusters reach 4 σ significance,the result of this work can not be considered to show the evidence of γ ray bursts; instead it just indicats that the air shower array of Tibet HD now has higher sensitivity for γ ray bursts compared to that of Tibet Ⅰ and Ⅱ. Much higher sensitivity in near future is expected to give clear evidence of 1-100 TeV γ ray bursts.