Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
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DOI：
10.1093/pasj/psx156
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发表时间：
2018-03-01
影响因子：
2.3
通讯作者：
Raassen, A. J. J.
中科院分区：
文献类型：
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作者：
Aharonian, Felix;Akamatsu, Hiroki;Raassen, A. J. J.
英仙星团的Hitomi软X射线光谱仪在2-9 keV波段的分辨率接近5 eV，为热碰撞等离子体的原子建模和数据库提供了前所未有的基准。它揭示了当前原子数据和模型的成功和挑战。AtomDB/APEC（3.0.8）、dac（3.03.00）和CHIANTI（8.0）的最新版本都提供了对宽带光谱的合理拟合，并且在最佳拟合温度、发射测量和一些元素（如Ni）的丰度方面非常一致。对于Fe丰度，APEC和DAC测量值相差16%，这是统计不确定性的17倍。这主要归因于最强发射线的碰撞激发和双电子复合速率的差异。我们进一步调查和比较的敏感性导出的物理参数的天体物理源建模和仪器的影响。Hitomi的结果表明，准确的原子数据和模型与天体物理建模和仪器校准方面一样重要。需要对原子数据库和有针对性的实验室测量进行实质性更新，以便为下一次Hitomi级使命的数据做好当前数据和模型的准备。
The Hitomi Soft X-ray Spectrometer spectrum of the Perseus cluster, with similar to 5 eV resolution in the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic data and models. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that accurate atomic data and models are as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current data and models ready for the data from the next Hitomi-level mission.