Detection of Multi-TeV Gamma Rays from Markarian 501 during an Unforeseen Flaring State in 1997 with the Tibet Air Shower Array
Detection of Multi-TeV Gamma Rays from Markarian 501 during an Unforeseen Flaring State in 1997 with the Tibet Air Shower Array
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DOI：
10.1086/308558
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发表时间：
2000-02
期刊：
影响因子：
--
通讯作者：
M. Amenomori;et al.
中科院分区：
文献类型：
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作者：
M. Amenomori;et al.
1997年，蝎虎座BL型天体Mrk 501进入一个非常活跃的阶段，是太电子伏能量下天空中最亮的源，表现出强烈且频繁的耀发。利用自1996年以来在西藏羊八井成功运行的一个高密度大气簇射阵列所获得的数据，我们在1997年2月至8月期间搜索了来自这个源的γ射线信号。我们的观测在这期间探测到了3.7倍标准差水平的多太电子伏γ射线信号。在4月7日至6月16日之间观测到超出计数的最快速增加，并且这一时期超出计数的统计显著性为4.7倍标准差。在1997年对Mrk 501的太电子伏γ射线耀发的若干观测中，这是唯一使用常规大气簇射阵列的观测。我们给出了γ射线的能谱，它将值得与成像大气切伦科夫望远镜所获得的能谱进行比较。
In 1997, the BL Lac object Mrk 501 entered a very active phase and was the brightest source in the sky at TeV energies, showing strong and frequent flaring. Using the data obtained with a high-density air shower array that has been operating successfully at Yangbajing in Tibet since 1996, we searched for γ-ray signals from this source during the period in 1997 from February through August. Our observation detected multi-TeV γ-ray signals at the 3.7 σ level during this period. The most rapid increase in the excess counts was observed between April 7 and June 16, and the statistical significance of the excess counts in this period was 4.7 σ. Among several observations of flaring TeV γ-rays from Mrk 501 in 1997, this is the only observation using a conventional air shower array. We present the energy spectrum of γ-rays, which will be worth comparing with those obtained by imaging atmospheric Cerenkov telescopes.