The spectrum of Th-Ar hollow-cathode lamps in the 900-4500 nm region: establishing wavelength standards for the calibration of VLT spectrographs
The spectrum of Th-Ar hollow-cathode lamps in the 900-4500 nm region: establishing wavelength standards for the calibration of VLT spectrographs
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900-4500 nm 区域的 Th-Ar 空心阴极灯光谱：为 VLT 摄谱仪校准建立波长标准
DOI：
10.1117/12.670361
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发表时间：
2006
影响因子：
3.2
通讯作者：
M. Rosa
中科院分区：
文献类型：
--
作者：
F. Kerber;G. Nave;C. Sansonetti;P. Bristow;A. Rosa;H. Käufl;M. Rosa
欧洲南方天文台（ESO）、欧洲空间望远镜协调设施（ST-ECF）和美国国家标准与技术研究所（NIST）正在合作研究用于校准VLT（甚大望远镜）光谱仪的Th-Ar空心阴极灯。在近红外波段，只有有限数量的波长标准可用。例如，在Ne或Kr灯中，线的密度和分布不足以用于高分辨率光谱。钍氩空心阴极灯在紫外可见区具有丰富的光谱，在天文学中应用已久；目前在ESO的例子包括光谱仪UVES和flame。大约在20年前，人们就以高分辨率研究了278 nm至约1000 nm的Th光谱（Palmer and Engleman, 1983）。最近发表了两项关于近红外Th-Ar光谱的研究，但这两项研究都不能直接应用于ESO红外天文光谱仪的校准。我们报告了使用NIST的2米紫外/可见/红外傅立叶变换光谱仪（FTS）的新测量结果，在900 nm至4500 nm范围内建立了2000多条谱线作为波长标准。该谱线列表用作物理模型的输入，该模型为低温高分辨率红外梯队光谱仪（CRIRES）提供波长校准，CRIRES是ESO在VLT的新高分辨率（R~100,000）红外光谱仪。我们还介绍了CRIRES实验室测试的第一个校准结果。新建立的波长标准也可用于x -射手和其他光谱仪在未来。测量Th-Ar灯的光谱随工作电流的变化，使我们能够根据望远镜操作的相对强度和线密度来优化光谱输出。由于Th线和Ar线强度对工作电流的响应不同，因此这种测量可以用作区分气体线和金属线的诊断工具。我们的研究结果表明，钍氩灯有望成为近红外天文学波长校准的标准光源。
The European Southern Observatory (ESO), the Space Telescope European Co-ordinating Facility (ST-ECF), and the US National Institute of Standards and Technology (NIST) are collaborating to study Th-Ar hollow cathode lamps as used for the calibration of VLT (Very Large Telescope) spectrographs. In the near IR only a limited number of wavelength standards are available. The density and distribution of lines in Ne or Kr lamps, for example, are inadequate for high-resolution spectroscopy. Th-Ar hollow cathode lamps provide a rich spectrum in the UV-visible region and have been used in astronomy for a long time; current examples at ESO include the spectrographs UVES and FLAMES. The Th spectrum from 278 nm to about 1000 nm was studied at high resolution about 20 years ago (Palmer and Engleman, 1983). Two studies of the Th-Ar spectrum in the near IR have recently been published, but neither work is directly applicable to the calibration of IR astronomical spectrographs at ESO. We report new measurements using the 2-m UV/visible/IR Fourier transform spectrometer (FTS) at NIST that establish more than 2000 lines as wavelength standards in the range 900 nm to 4500 nm. This line list is used as input for a physical model that provides the wavelength calibration for the Cryogenic High-Resolution IR Echelle Spectrometer (CRIRES), ESO's new high resolution (R~100,000) IR spectrograph at the VLT. We also present first calibration results from laboratory testing of CRIRES. The newly established wavelength standards will also be available for use by X-shooter and other spectrographs in the future. Measurements of the variation of the spectrum of Th-Ar lamps as a function of operating current allow us to optimise the spectral output in terms of relative intensity and line density for operation on the telescope. Since Th and Ar line intensities show a different response with respect to operating current, such measurements can be used as a diagnostic tool for distinguishing the gas and metal lines. Our findings show that Th-Ar lamps hold the promise of becoming a standard source for wavelength calibration in near IR astronomy.