Imaging from STIX visibility amplitudes
Imaging from STIX visibility amplitudes
复制标题
DOI：
10.1051/0004-6361/202140946
复制
发表时间：
2021-12-14
影响因子：
6.5
通讯作者：
Krucker, Sam
中科院分区：
文献类型：
--
作者：
Massa, Paolo;Perracchione, Emma;Krucker, Sam
目标。该研究旨在提供STIX傅里叶变换x射线成像的首次演示，使用在太阳轨道飞行器巡航阶段获得的半校准（仅振幅）可见性数据。方法。我们使用了参数成像方法，其中STIX可见性振幅通过两种非线性优化方法进行拟合：一种受社会行为启发的快速元启发式技术和贝叶斯蒙特卡罗采样方法，尽管较慢，但提供了一种更好的量化不确定性的方法。结果。当应用于2020年11月18日STIX记录的一组太阳耀斑可见幅度时，两种参数方法提供了非常一致的结果。分析还证明了STIX在高时间分辨率下重建数据的能力，并且从光谱的角度来看，它显示了与热解释和非热解释一致的双源情景的可靠性。结论。在这个仅基于可见幅度的STIX成像的初步分析中，我们将成像问题描述为一个非线性参数问题，通过两种高性能优化技术来解决，这两种技术都显示了以有效方式对参数空间进行采样的能力，从而避免了任何局部最小值。
Aims. This study is aimed at providing the first demonstration of STIX Fourier-transform X-ray imaging using semi-calibrated (amplitude-only) visibility data acquired during Solar Orbiter's cruise phase. Methods. We used a parametric imaging approach whereby STIX visibility amplitudes are fitted by means of two non-linear optimization methods: a fast meta-heuristic technique inspired by social behavior and a Bayesian Monte Carlo sampling method that, although slower, provides a better way of quantifying the uncertainties. Results. When applied to a set of solar flare visibility amplitudes recorded by STIX on November 18, 2020, the two parametric methods provide very coherent results. The analysis also demonstrates the ability of STIX to reconstruct data at a high time resolution and, from a spectral viewpoint, it shows the reliability of a double-source scenario that is consistent with a thermal versus nonthermal interpretation. Conclusions. In this preliminary analysis of STIX imaging based only on visibility amplitudes, we formulate the imaging problem as a non-linear parametric issue addressed by means of two high-performance optimization techniques that both show the ability to sample the parametric space in an effective fashion, thus avoiding any local minima.