ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2
ON-SKY PERFORMANCE ANALYSIS OF THE VECTOR APODIZING PHASE PLATE CORONAGRAPH ON MagAO/Clio2
复制标题
MagAO/Clio2 上矢量变迹相位板日冕仪的在空性能分析
DOI：
10.3847/1538-4357/834/2/175
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Escuti
中科院分区：
文献类型：
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作者：
G. Otten;F. Snik;M. Kenworthy;C. Keller;J. Males;K. Morzinski;L. Close;J. Codona;P. Hinz;Kathryn J. Hornburg;Leandra L. Brickson;M. Escuti
本文报道了安装在智利拉斯坎帕纳斯天文台的6.5 m麦哲伦克莱望远镜上的MagAO/Clio2中，工作波长范围为2-5 μm的矢量apodizing相位板日冕仪的性能。日冕仪操纵瞳孔中的相位产生三束，产生两个日冕点扩展函数（PSF）和一个微弱泄漏PSF。相位图案是通过固有的消色差几何相位施加的，由液晶技术和偏振技术实现。使用直接写入技术来精确控制液晶图案和用于消色差的多捻缓速器来制造日冕光学。通过将线性相位坡道集成到日冕相位模式中，两个分离的日冕psf使用单个瞳孔平面光学元件，这使得它坚固耐用，易于安装在现有的望远镜中。两个日冕psf在恒星的两侧各有一个180°的黑洞，这些互补的恒星副本被用来校正靠近恒星的视晕。为了表征日冕仪，我们收集了一颗明亮（mL = 0-1）的附近恒星的数据集，观测时间为~ 1.5小时。通过旋转和优化缩放一个PSF并从另一个PSF中减去它，我们看到3.5 λ / D时对比度提高了1.46个数量级。在3.9 μm的正角差成像下，MagAO矢量apodizing相位板日冕仪在2 λ / D下提供了8.3（= 10−3.3）和12.2（= 10−4.8）的5 σ Δ反差。
We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of 2–5 μm and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The coronagraph manipulates the phase in the pupil to produce three beams yielding two coronagraphic point-spread functions (PSFs) and one faint leakage PSF. The phase pattern is imposed through the inherently achromatic geometric phase, enabled by liquid crystal technology and polarization techniques. The coronagraphic optic is manufactured using a direct-write technique for precise control of the liquid crystal pattern and multitwist retarders for achromatization. By integrating a linear phase ramp to the coronagraphic phase pattern, two separated coronagraphic PSFs are created with a single pupil-plane optic, which makes it robust and easy to install in existing telescopes. The two coronagraphic PSFs contain a 180° dark hole on each side of a star, and these complementary copies of the star are used to correct the seeing halo close to the star. To characterize the coronagraph, we collected a data set of a bright (mL = 0–1) nearby star with ∼1.5 hr of observing time. By rotating and optimally scaling one PSF and subtracting it from the other PSF, we see a contrast improvement by 1.46 magnitudes at 3.5 λ / D . With regular angular differential imaging at 3.9 μm, the MagAO vector apodizing phase plate coronagraph delivers a 5 σ Δ mag contrast of 8.3 ( = 10 − 3.3 ) at 2 λ / D and 12.2 ( = 10 − 4.8 ) at 3.5 λ / D .