We present the precise wavelength calibration of a high-resolution spectrum using uranium (U) lines in the wavelength range of 3809 to 6833 Å for precision radial velocity (RV) measurements for exoplanet detection or related astrophysical sciences. We identify 1540 well-resolved U lines from a high-resolution (R = 67 , 000) spectrum of the uranium-argon hollow cathode lamp (UAr HCL) using PARAS spectrograph in the aforesaid wavelength range. We calculate the neutral and first allowed transitions (Ritz wavelength) of U from its known energy levels and compare them with our observed central wavelengths. We measure an offset of −0.15 mÅ in our final U line list. The line list has an average measurement uncertainty of 15 ms − 1 (0.013 pixels or 0.28 mÅ). We included these lines to the PARAS data analysis framework to perform the wavelength calibration and then calculate the multi-order RV of PARAS spectra. The typical dispersion of residuals around the wavelength solution of a UAr spectrum, using U lines, is found to be 0.8 mÅ (∼45 m s − 1). With the use of this line list, we present our results for the precision RV of an on-sky source (an RV standard star) and an off-sky source (an HCL) observed with PARAS along with UAr HCL. We measure the dispersion in absolute drift difference between two fibers (inter-fiber drift) for a span of 6.5 h to be 88 cm s − 1, and the RV dispersion (σRV) for an RV standard star, HD55575 over the course of ∼450 days to be 3.2 m s − 1. These results are in good agreement with the previous ones measured using the ThAr HCL. It proves that the ThAr HCL with ∼99 % pure-Th is replaceable with the UAr HCL for the wavelength calibration of the high-resolution spectrographs such as PARAS (R ≤ 67,000) to achieve an RV precision of 1 to 3 m s − 1 in the visible region.

中文翻译：

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使用 3800 至 6900 Å 铀线对径向速度测量进行精密波长校准

我们使用 3809 至 6833 Å 波长范围内的铀 (U) 谱线对高分辨率光谱进行精确波长校准，用于系外行星探测或相关天体物理科学的精确径向速度 (RV) 测量。我们使用 PARAS 光谱仪在上述波长范围内从铀 - 氩空心阴极灯 (UAr HCL) 的高分辨率 (R = 67, 000) 光谱中识别出 1540 条分辨率良好的 U 线。我们根据已知能级计算 U 的中性跃迁和第一个允许跃迁（里兹波长），并将它们与我们观察到的中心波长进行比较。我们在最终的 U 线列表中测量了 -0.15 mÅ 的偏移。线列表的平均测量不确定度为 15 ms − 1（0.013 像素或 0.28 mÅ）。我们将这些线包含在 PARAS 数据分析框架中以执行波长校准，然后计算 PARAS 光谱的多阶 RV。发现使用 U 线的 UAr 光谱波长解周围的残余物的典型色散为 0.8 mÅ (∼45 m s − 1)。使用此行列表，我们展示了使用 PARAS 和 UAr HCL 观测到的在天源（RV 标准星）和离天源（HCL）的精确 RV 结果。我们测量了 6.5 小时跨度内两根光纤之间的绝对漂移差（光纤间漂移）的色散为 88 cm s − 1，以及 RV 标准星 HD55575 的 RV 色散 (σRV) 在 ∼ 450 天为 3.2 ms − 1。这些结果与之前使用 ThAr HCL 测量的结果非常一致。