标题： 研究光学像差对衍射极限径向速度仪器的影响 显示英文标题

标题： Studying the Impact of Optical Aberrations on Diffraction-Limited Radial Velocity Instruments

摘要： 光谱仪通常包含一定量的准静态光学像差，这些像差来源于制造部件表面的质量、对准不完善、设计残余、热效应以及其他在设计和制造过程中涉及的相关现象。随时间变化的像差可能会模仿多普勒位移的线中心运动，引入径向速度（RV）不确定性，从而增加时间序列的变异性。即使使用精确的波长校准光源来跟踪仪器漂移，地球的质心运动也会导致恒星光的波长偏移，使得光谱在焦平面阵列上移动多个像素。波长偏移使得吸收线在观测时期内经历不同的光学传播路径和像差。我们使用物理光学传播模拟来研究像差对衍射极限、高分辨率光谱仪进行的精确多普勒测量的影响。我们量化了在存在像差和质心 RV 移位的情况下，交叉相关技术引入的不确定性。我们发现，特别是在色散方向上移动点扩散函数光中心的像差，如初级水平彗差和三叶形像差，最为值得关注。为了保持由像差引起的 RV 误差小于 10 cm/s，在仪器工作波长处，这些特定像差的相位误差必须严格低于 0.05 波长。我们的模拟进一步表明，由于交叉相关技术在处理恒星光与校准光时对像差的处理行为不同，波长校准只能部分补偿仪器漂移。识别影响 RV 误差的细微物理效应将有助于确保衍射极限的系外行星探测光谱仪能够充分发挥其科学潜力。 显示英文摘要

摘要： Spectrographs nominally contain a degree of quasi-static optical aberrations resulting from the quality of manufactured component surfaces, imperfect alignment, design residuals, thermal effects, and other other associated phenomena involved in the design and construction process. Aberrations that change over time can mimic the line centroid motion of a Doppler shift, introducing radial velocity (RV) uncertainty that increases time-series variability. Even when instrument drifts are tracked using a precise wavelength calibration source, barycentric motion of the Earth leads to a wavelength shift of stellar light causing a translation of the spectrum across the focal plane array by many pixels. The wavelength shift allows absorption lines to experience different optical propagation paths and aberrations over observing epochs. We use physical optics propagation simulations to study the impact of aberrations on precise Doppler measurements made by diffraction-limited, high-resolution spectrographs. We quantify the uncertainties that cross-correlation techniques introduce in the presence of aberrations and barycentric RV shifts. We find that aberrations which shift the PSF photo-center in the dispersion direction, in particular primary horizontal coma and trefoil, are the most concerning. To maintain aberration-induced RV errors less than 10 cm/s, phase errors for these particular aberrations must be held well below 0.05 waves at the instrument operating wavelength. Our simulations further show that wavelength calibration only partially compensates for instrumental drifts, owing to a behavioral difference between how cross-correlation techniques handle aberrations between starlight versus calibration light. Identifying subtle physical effects that influence RV errors will help ensure that diffraction-limited planet-finding spectrographs are able to reach their full scientific potential.