arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0704.3637astro-ph
收藏

G波段对比度的差异:安静的太阳在哪里?

The discrepancy in G-band contrast: Where is the quiet Sun?

Han Uitenbroek, Alexandra Tritschler, Thomas Rimmele

摘要:

我们比较观察到的斑点重建G波段图像的均方根对比度从两个磁流体动力学模拟快照计算的合成滤波图。这些观测由邓恩太阳望远镜(DST)拍摄的103次爆发组成,每次80帧,以望远镜衍射极限的两倍采样。散斑重建说明了DST处的自适应光学(AO)系统的性能,以提供可靠的光度测定。我们发现一个相当大的差异,在观察到的均方根对比度为14.1%的最佳重建图像,和合成均方根对比度为21.5%的模拟快照被认为是代表安静的太阳。合成滤波图中具有超出重建图像中最小值和最大值的正或负对比度的特征区域具有应该解析的空间尺度。这使我们得出结论,有根本的差异,均方根G波段对比度之间的观测和计算的滤波图。根据合成谱带滤波图中16.3%的颗粒对比度大幅降低,我们推测宁静太阳可能包含比以前认为的更弱的磁场。

英文摘要:

We compare the rms contrast in observed speckle reconstructed G-band images with synthetic filtergrams computed from two magneto-hydrodynamic simulation snapshots. The observations consist of 103 bursts of 80 frames each taken at the Dunn Solar Telescope (DST), sampled at twice the diffraction limit of the telescope. The speckle reconstructions account for the performance of the Adaptive Optics (AO) system at the DST to supply reliable photometry. We find a considerable discrepancy in the observed rms contrast of 14.1% for the best reconstructed images, and the synthetic rms contrast of 21.5% in a simulation snapshot thought to be representative of the quiet Sun. The areas of features in the synthetic filtergrams that have positive or negative contrast beyond the minimum and maximum values in the reconstructed images have spatial scales that should be resolved. This leads us to conclude that there are fundamental differences in the rms G-band contrast between observed and computed filtergrams. On the basis of the substantially reduced granular contrast of 16.3% in the synthetic plage filtergram we speculate that the quiet-Sun may contain more weak magnetic field than previously thought.

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。

↑