升级LBTI/NOMIC以使用四重环形槽相位掩模和GeoSnap探测器对邻近宜居带系外行星进行成像
Upgrading LBTI/NOMIC with a quadruple annular groove phase mask and GeoSnap detector for imaging nearby, habitable-zone exoplanets
浏览论文内容
中文总结 AI 辅助
该研究为LBTI/NOMIC升级Q-AGPM日冕仪与GeoSnap阵列，结合FFTCam验证干涉增益，以实现对邻近类太阳恒星宜居带系外行星的高对比度成像观测
中文摘要 AI 辅助
大双筒望远镜干涉仪（LBTI）的消零优化中红外相机（NOMIC）是用于高对比度、高角分辨率天文观测的最先进热红外成像系统之一。本文描述了LBTI/NOMIC正在进行的两项升级：（1）四重环形槽相位掩模（Q-AGPM）日冕仪的设计、制造与安装；（2）13微米截止的Teledyne GeoSnap阵列的安装。Q-AGPM是首个安装在NOMIC内的日冕仪，也是首批针对N波段（约11微米）观测优化的日冕仪之一，它将四个环形槽相位掩模置于单个金刚石基底上，使LBTI双孔径成像模式下，两个望远镜光束均可在一对掩模间切换而不损失观测效率。GeoSnap阵列将取代NOMIC原有的AQUARIUS阵列，提供更高的量子效率、更大的阱深、更快且更线性的读出，以及无需剧烈切趾的额外低频噪声抑制。这些升级共同大幅提升了小角距下可实现的对比度和灵敏度。我们还展示了使用LBTI新型FFTCam条纹跟踪器获得的高对比度斐索成像序列，通过注入/恢复测试证实了干涉测量相对于单孔径的增益：在0.2-1角秒范围内，信噪比为3时的对比度比等时单孔径曝光深约2-4倍，覆盖对比度限制和背景限制区域。最后，我们描述了升级后的LBTI/NOMIC仪器在亚利桑那大学突破观测计划中的作用，该计划旨在对最近的单颗类太阳恒星的宜居带进行迄今最深的观测。
英文摘要
The Large Binocular Telescope Interferometer (LBTI)'s Nulling-Optimized Mid-Infrared Camera (NOMIC) is among the most capable thermal-infrared imaging systems available for high-contrast, high-angular-resolution astronomical observations. Here we describe two in-progress upgrades to LBTI/NOMIC: (1) the design, fabrication, and installation of a quadruple annular groove phase mask (Q-AGPM) coronagraph, and (2) the installation of a 13 micron-cutoff Teledyne GeoSnap array. The Q-AGPM is the first coronagraph to be installed within NOMIC and one of the first optimized for N-band (~11 micron) observations. It places four annular groove phase masks on a single diamond substrate so that, in the LBTI dual-aperture imaging mode, each of the two telescope beams can be chopped between a pair of masks without loss of observing efficiency. The GeoSnap array will replace NOMIC's original AQUARIUS array, delivering higher quantum efficiency, larger well depth, faster and more linear readout, and freedom from the excess low-frequency noise that requires aggressive chopping. Together these upgrades substantially improve the achievable contrast and sensitivity at small angular separations. We also present a high-contrast Fizeau imaging sequence obtained with LBTI's new FFTCam fringe tracker, which confirms the interferometric gain over a single aperture through injection/recovery tests: relative to an equal-time single aperture exposure, the S/N = 3 contrast is a factor of ~2-4 deeper across 0.2-1 arcsec, spanning the contrast- and background-limited regimes. Finally, we describe the role of the upgraded LBTI/NOMIC instrument within the Breakthrough Watch program at the University of Arizona, which aims to perform the deepest observations yet of the habitable zones of the nearest single Sun-like stars.
