Origin of the asymmetry of the wind driven halo observed in high-contrast images
Origin of the asymmetry of the wind driven halo observed in high-contrast images
复制标题
高对比度图像中观察到的风驱动晕不对称的起源
DOI：
--
复制
发表时间：
2018
影响因子：
6.5
通讯作者：
T. Fusco
中科院分区：
文献类型：
--
作者：
F. Cantalloube;E. Por;K. Dohlen;J. Sauvage;A. Vigan;M. Kasper;N. Bharmal;T. Henning;W. Brandner;J. Milli;C. Correia;T. Fusco
最新一代的高对比度仪器专门用于系外行星和星周盘成像，配备了极端的自适应光学和日冕仪，在近红外线的十分之几角秒处达到高达10−4的对比度。由此产生的图像显示出微弱的特征，只有在这种组合下才能显示出来，例如风驱动的光环。风驱动晕是由于自适应光学校正和望远镜瞳孔上的湍流速度之间的滞后。然而，我们观察到这种风驱动的晕轮的不对称性，这是仪器设计时所没有预料到的。在这封信中，我们描述和证明了这种不对称性的物理起源，并支持我们的解释，通过模拟的不对称性与端到端的方法。从这项工作中，我们发现，所观察到的不对称性解释的AO滞后误差和闪烁效应之间的干扰，主要来自快速急流层位于约12公里的高度。现在识别和解释，这种效果可以考虑进一步设计的高对比度成像模拟器，下一代或升级的高对比度仪器，自适应光学的预测控制算法，或图像后处理技术。
The latest generation of high-contrast instruments dedicated to exoplanets and circumstellar disk imaging are equipped with extreme adaptive optics and coronagraphs to reach contrasts of up to 10−4 at a few tenths of arcseconds in the near-infrared. The resulting image shows faint features, only revealed with this combination, such as the wind driven halo. The wind driven halo is due to the lag between the adaptive optics correction and the turbulence speed over the telescope pupil. However, we observe an asymmetry of this wind driven halo that was not expected when the instrument was designed. In this letter, we describe and demonstrate the physical origin of this asymmetry and support our explanation by simulating the asymmetry with an end-to-end approach. From this work, we find that the observed asymmetry is explained by the interference between the AO-lag error and scintillation effects, mainly originating from the fast jet stream layer located at about 12 km in altitude. Now identified and interpreted, this effect can be taken into account for further design of high-contrast imaging simulators, next generation or upgrade of high-contrast instruments, predictive control algorithms for adaptive optics, or image post-processing techniques.