朱雀号X射线成像光谱仪非X射线本底的再现
Reproducibility of Non-X-ray Background for the X-ray Imaging Spectrometer aboard Suzaku
摘要：
朱雀号上的X射线成像光谱仪（XIS）系统的优点之一是其低而稳定的非X射线背景（NXB）。为了充分利用这一优势，以高精度对NXB光谱进行建模对于从源上观测的光谱中减去它们是很重要的。我们建立了一个NXB数据库，收集XIS事件时，黑暗的地球覆盖的XIS FOV。对于每个XIS，NXB数据的总曝光时间约为785 ks。发现NXB的计数率与截止刚度呈反相关，与朱雀号硬X射线探测器的PIN上表面（PIN-UD）计数率呈相关。因此，我们通过采用这些参数中的任一个对给定源上观测的NXB谱进行建模，并且对于具有PIN-UD的模型，比具有截止刚度的模型获得了更好的NXB再现性。对于NXB数据的每5 ks曝光，具有PIN-UD的NXB模型的再现性对于1-7 keV频带中的每个XIS NXB为4.55-5.63%，对于5-12 keV频带中的每个XIS NXB为2.79-4.36%。这种NXB再现性比宇宙X射线背景在1-7 keV波段的空间起伏小得多，与5-12 keV波段的空间起伏几乎相当。
英文摘要：
One of the advantages of the X-ray Imaging Spectrometer (XIS) system on board Suzaku is its low and stable non-X-ray background (NXB). In order to make the best use of this advantage, modeling the NXB spectra with high accuracy is important to subtract them from the spectra of on-source observations. We construct an NXB database by collecting XIS events when the dark Earth covers the XIS FOV. The total exposure time of the NXB data is about 785 ks for each XIS. It is found that the count rate of the NXB anti-correlates with the cut-off-rigidity and correlates with the count rate of the PIN upper discriminator (PIN-UD) in Hard X-ray Detector on board Suzaku. We thus model the NXB spectrum for a given on-source observation by employing either of these parameters and obtain a better reproducibility of the NXB for the model with PIN-UD than that with the cut-off-rigidity. The reproducibility of the NXB model with PIN-UD is 4.55-5.63% for each XIS NXB in the 1-7 keV band and 2.79-4.36% for each XIS NXB in the 5-12 keV band for each 5 ks exposure of the NXB data. This NXB reproducibility is much smaller than the spatial fluctuation of the cosmic X-ray background in the 1-7 keV band, and is almost comparable to that in the 5-12 keV band.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
