TESTING EUV/X-RAY ATOMIC DATA FOR THE SOLAR DYNAMICS OBSERVATORY
TESTING EUV/X-RAY ATOMIC DATA FOR THE SOLAR DYNAMICS OBSERVATORY
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测试太阳动力学观测站的 EUV/X 射线原子数据
DOI：
10.1088/0004-637x/745/2/111
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
E. Landi
中科院分区：
文献类型：
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作者：
P. Testa;J. Drake;E. Landi
太阳动力学观测台上的大气成像装置和极紫外线可变性实验包括X射线/极紫外波段的光谱窗口。在这个波长范围内原子数据的准确性和完整性对于解释日冕的光谱和辐照度以及用AIA和EVE仪器进行的SDO观测至关重要。在这里，我们测试了CHIANTI数据库中的X射线/EUV数据，以评估它们在SDO波段的完整性和准确性，特别关注94 kHz和131 kHz AIA通带。由于缺乏足够的太阳观测，我们使用高分辨率的X射线光谱的低活性太阳一样的日冕的南河三获得的钱德拉低能量透射光栅光谱仪（LETGS）。我们发现，虽然光谱模型总体上可以很好地再现在软X射线范围λ <$50 nm和极紫外波长λ <$130 nm处观察到的光谱，但它们显著低估了在50-130 nm波长范围内观察到的通量。该模型低估了观测到的通量，低估的可变因子范围从1.5（低于150 nm的短波长）到1.5 -7（70-125 nm范围）。在LETGS覆盖的AIA频段中，即，94 μ m和131 μ m，我们发现观测到的通量可以被大的因子低估（对于这里提出的南河三的情况，分别为1.3和1.9）。我们讨论了AIA数据分析的后果和可能的经验修正AIA响应模型更现实地在这些通带的日冕发射。
The Atmospheric Imaging Assembly (AIA) and the Extreme-ultraviolet Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) include spectral windows in the X-ray/EUV band. Accuracy and completeness of the atomic data in this wavelength range is essential for interpretation of the spectrum and irradiance of the solar corona, and of SDO observations made with the AIA and EVE instruments. Here, we test the X-ray/EUV data in the CHIANTI database to assess their completeness and accuracy in the SDO bands, with particular focus on the 94 Å and 131 Å AIA passbands. Given the paucity of solar observations adequate for this purpose, we use high-resolution X-ray spectra of the low-activity solar-like corona of Procyon obtained with the Chandra Low Energy Transmission Grating Spectrometer (LETGS). We find that while spectral models overall can reproduce quite well the observed spectra in the soft X-ray range λ ≲ 50 Å, and at the EUV wavelengths λ ≳ 130 Å, they significantly underestimate the observed flux in the 50–130 Å wavelength range. The model underestimates the observed flux by a variable factor ranging from ≈1.5, at short wavelengths below ∼50 Å, up to ≈5–7 in the ∼70–125 Å range. In the AIA bands covered by LETGS, i.e., 94 Å and 131 Å, we find that the observed flux can be underestimated by large factors (∼3 and ∼1.9, respectively, for the case of Procyon presented here). We discuss the consequences for analysis of AIA data and possible empirical corrections to the AIA responses to model more realistically the coronal emission in these passbands.