论文标题
excalibur：一种非参数，分层波长 - 校准方法，用于精确光谱仪
Excalibur: A Non-Parametric, Hierarchical Wavelength-Calibration Method for a Precision Spectrograph
论文作者
论文摘要
Excalibur是一种非参数，分层框架，用于光谱仪的精确波长校准。它的设计是考虑到极端精确的径向速度（EPRV）的需求，它要求校准或稳定仪器，比$ 10^{ - 4} $像素更好。仪器只有几个主要的自由度，尤其是具有高度稳定的光学系统和检测器的EPRV仪器。 Excalibur通过使用所有校准数据来利用此属性来构建仪器所有可访问校准状态的低维表示。 Excalibur还利用激光频率梳子或Etalon，产生一组密集的稳定校准点。该密度允许使用非参数波长解决方案，该解决方案可以比参数模型（例如多项式）更好地适应任何仪器或检测器奇数。我们通过使用激光频率梳的极限光谱仪（Expres）的数据证明了这种方法的成功。当使用Excalibur将波长分配给激光梳线时，残差的RMS比使用多项式拟合分配给单个暴露的波长低约五倍。 HD 34411的径向速度测量结果显示，RMS在10个月的基线中散布从$ 1.17 $降至$ 1.05 \，M \，S^{ - 1} $。
Excalibur is a non-parametric, hierarchical framework for precision wavelength-calibration of spectrographs. It is designed with the needs of extreme-precision radial velocity (EPRV) in mind, which require that instruments be calibrated or stabilized to better than $10^{-4}$ pixels. Instruments vary along only a few dominant degrees of freedom, especially EPRV instruments that feature highly stabilized optical systems and detectors. Excalibur takes advantage of this property by using all calibration data to construct a low-dimensional representation of all accessible calibration states for an instrument. Excalibur also takes advantage of laser frequency combs or etalons, which generate a dense set of stable calibration points. This density permits the use of a non-parametric wavelength solution that can adapt to any instrument or detector oddities better than parametric models, such as a polynomial. We demonstrate the success of this method with data from the EXtreme PREcision Spectrograph (EXPRES), which uses a laser frequency comb. When wavelengths are assigned to laser comb lines using excalibur, the RMS of the residuals is about five times lower than wavelengths assigned using polynomial fits to individual exposures. Radial-velocity measurements of HD 34411 showed a reduction in RMS scatter over a 10-month time baseline from $1.17$ to $1.05\, m\,s^{-1}$.
