Observations of the Crab Nebula with H.E.S.S
Observations of the Crab Nebula with H.E.S.S
复制标题
DOI：
10.1051/0004-6361:20065351
复制
发表时间：
2006-07
期刊：
影响因子：
--
通讯作者：
The Hess Collaboration F.Aharonian;E. al.
中科院分区：
文献类型：
--
作者：
The Hess Collaboration F.Aharonian;E. al.
上下文。2003年10月至2005年1月期间，利用H.E.SS立体切伦科夫望远镜阵列观测了蟹状星云，总共观测了22.9小时(经过数据质量选择)。这段时间与试验的试运行阶段部分重叠；2003年底用三个可操作的望远镜进行观测，2004年1月至2月和2004年10月至2005年1月用完整的4号望远镜阵列进行观测。目标。对蟹状星云的观测进行了讨论，并以此为例详细介绍了H.E.S.的flUX和光谱分析程序。该结果被用于评估H.E.S.flUX测量的系统不确定度。方法：研究方法。蟹状星云的数据是使用标准的H.E.S.S.分析程序进行分析的，详细描述了这些程序。在逐个运行和每月的时间尺度上计算来自源的flUX和γ射线的光谱，并对探测器灵敏度的长期变化进行校正。使用在观察期内测量的flUX和频谱的比较，以及一些不同分析程序的结果来估计测量中的系统不确定度。结果。这些数据是在45◦到65◦之间的天顶角范围内获取的，显示了超过7,500个额外事件的明确信号。能谱服从指数Cutoff的幂规律，光子指数Γ=2。39±0。03Stat和Cutoff能量Ec=(14.3±2。1STAT)TeV在440GeV到40TeV之间。观测到的大于1TeV的积分flUX为(2。26±0。08 Stat)×10−11 cm−2 S−1.flUX测量的系统误差估计为20%，而频谱斜率的系统误差估计为0.1。
Context. The Crab nebula was observed with the H.E.S.S. stereoscopic Cherenkov-telescope array between October 2003 and January 2005 for a total of 22.9 hours (after data quality selection). This period of time partly overlapped with the commissioning phase of the experiment; observations were made with three operational telescopes in late 2003 and with the complete 4 telescope array in January – February 2004 and October 2004 – January 2005. Aims. Observations of the Crab nebula are discussed and used as an example to detail the flux and spectral analysis procedures of H.E.S.S.. The results are used to evaluate the systematic uncertainties in H.E.S.S. flux measurements. Methods. The Crab nebula data are analysed using standard H.E.S.S. analysis procedures, which are described in detail. The flux and spectrum of γ -rays from the source are calculated on run-by-run and monthly time-scales, and a correction is applied for long-term variations in the detector sensitivity. Comparisons of the measured flux and spectrum over the observation period, along with the results from a number of di ff erent analysis procedures are used to estimate systematic uncertainties in the measurements. Results. The data, taken at a range of zenith angles between 45 ◦ and 65 ◦ , show a clear signal with over 7500 excess events. The energy spectrum is found to follow a power law with an exponential cuto ff , with photon index Γ = 2 . 39 ± 0 . 03 stat and cuto ff energy E c = (14 . 3 ± 2 . 1 stat )TeV between 440 GeV and 40 TeV. The observed integral flux above 1 TeV is (2 . 26 ± 0 . 08 stat ) × 10 − 11 cm − 2 s − 1 . The estimated systematic error on the flux measurement is estimated to be 20%, while the estimated systematic error on the spectral slope is 0.1.