Precise Spectroscopic Radial Velocity Measurements Using Telluric Lines
Precise Spectroscopic Radial Velocity Measurements Using Telluric Lines
复制标题
使用大地线进行精确的光谱径向速度测量
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Kevin I. T. Brown
中科院分区：
文献类型：
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作者：
D. F. Gray;Kevin I. T. Brown
我们的Coudé摄谱仪内的大地吸收被用作精确径向速度测量的参考光谱。这种大地吸收的光路是稳定的，不受大气扰动（如急流）的影响。作为额外的奖励，大地基准光谱是免费的;即，不需要构造、调节、维护捕获气体吸收池或遭受捕获气体吸收池的通量损失。大地光谱和恒星光谱跨越探测器的同一部分，并按顺序观察，但在不同的衍射级。这样，恒星线轮廓就不会被大地光谱污染，因此可以用于正常的天体物理线轮廓分析，以及径向速度研究。然而，需要对温度和压力进行精确测量以进行阶之间的差分校正，因为光谱仪中空气的折射率是波长相关的。径向速度的精度为1.25 m s−1。
Telluric absorption inside our coudé spectrograph is used as a reference spectrum for precise radial velocity measurement. The optical path for this telluric absorption is stable and is not compromised by atmospheric disturbances, such as the jet stream. As an added bonus, the telluric fiducial spectrum is free; i.e., one does not need to construct, regulate, maintain, or suffer throughput losses from a captive‐gas absorption cell. The telluric and stellar spectra span the same portion of the detector and are observed sequentially, but in different diffraction orders. In this way the stellar line profiles are not contaminated by the telluric spectrum and can therefore be used for normal astrophysical line profile analyses, as well as radial velocity studies. However, precise measurements of the temperature and pressure are needed for differential corrections between orders, because the index of refraction of the air in the spectrograph is wavelength dependent. Precision in radial velocity of ∼25 m s−1 is demonstrated.