用自相干相机进行天空暗区探测：初步结果
Digging dark holes on-sky with the Self-Coherent Camera: Preliminary results
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中文总结 AI 辅助
本研究利用自相干相机（SCC）的快速大气SCC技术（FAST），在麦哲伦望远镜上实现天空闭环演示，使暗区1σ原始对比度提升10倍，未来将结合相干差分成像进一步增强对比度。
中文摘要 AI 辅助
当前高对比度成像仪器受限于非共光路像差（NCPAs）产生的波前误差，这类误差源于光学元件制造误差、系统温度漂移等因素，会在最终科学图像中形成类静态散斑，难以与伴星区分，因此需要焦平面波前传感与控制来抑制散斑。自相干相机（SCC）是可估计恒星复散斑场的波前传感器，快速大气SCC技术（FAST）中，轴上恒星光线入射到日冕仪焦平面相位掩模后衍射出 Lyot 光瞳，经针孔空间滤波形成参考光束，参考光束与泄漏的恒星光线在科学平面重组，产生的干涉条纹因非相干性不会影响伴星；该焦平面掩模由莱顿大学内部采用双光子聚合实现亚微米高度精度的微3D打印机Nanoscribe制造。我们展示了智利拉斯坎帕纳斯天文台6.5米麦哲伦克莱望远镜搭载麦哲伦极端自适应光学（MagAO-X）仪器开展的首次SCC天空闭环演示的初步结果，通过FAST闭环控制，在目标暗区实现1σ原始对比度提升10倍。未来我们将开展带伴星恒星的观测，并在后续处理中以相干差分成像（CDI）技术使用SCC进一步提升对比度。
英文摘要
Current high-contrast imaging instruments are limited by wavefront errors originating from non-common path aberrations (NCPAs) due, for example, to manufacturing errors in the optics and temperature drifts in the system. These create quasi-static speckles in the final science image that are difficult to distinguish from companions. Therefore, focal plane wavefront sensing and control is needed to suppress speckles. The Self-Coherent Camera (SCC) is a wavefront sensor that allows us to estimate the stellar complex speckle field. In the Fast Atmospheric SCC Technique (FAST), the on-axis starlight hits a coronagraphic focal plane phase mask and is diffracted outside the Lyot stop where it is spatially filtered by a pinhole to create a reference beam. The reference beam and the leaked starlight are recombined on the science plane, creating interference fringes that do not affect the companion, because of incoherence. The focal plane mask was manufactured in-house at Leiden University with Nanoscribe, a micro-3D-printer that uses two-photon polymerization to achieve sub-micron precision in height. We present preliminary results of the first on-sky closed-loop SCC demonstration with the Magellan Adaptive Optics eXtreme (MagAO-X) instrument on the 6.5-meter Magellan Clay telescope at Las Campanas Observatory, Chile. We achieve a 1-sigma raw contrast improvement of a factor 10 in the desired dark hole region with FAST closed-loop control. In the future, we will show observations of stars with companions and use the SCC in post-processing as a Coherent Differential Imaging (CDI) technique to enhance the contrast even further.
