J/A+A/618/A118 Uranium line list (Sarmiento+, 2018) ================================================================================ Comparing the emission spectra of U and Th hollow cathode lamps and a new U line-list. Sarmiento L.F., Reiners A., Huke P., Bauer F.F., Guenter E.W., Seemann U., Wolter U. =2018A&A...618A.118S (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Atomic physics Keywords: catalogs - line: identification - techniques: spectroscopic - methods: data analysis Abstract: Thorium hollow cathode lamps (HCLs) are used as frequency calibrators for many high resolution astronomical spectrographs, some of which aim for Doppler precision at the 1m/s level. We aim to determine the most suitable combination of elements (Th or U, Ar or Ne) for wavelength calibration of astronomical spectrographs, to characterize differences between similar HCLs, and to provide a new U line list. We record high resolution spectra of different HCLs using a Fourier transform spectrograph: (i) U-Ne, U-Ar, Th-Ne, and Th-Ar lamps in the spectral range from 500 to 1000nm and U-Ne and U-Ar from 1000 to 1700nm; (ii) we systematically compare the number of emission lines and the line intensity ratio for a set of 12 U-Ne HCLs; and (iii) we record a master spectrum of U-Ne to create a new U line list. Uranium lamps show more lines suitable for calibration than Th lamps from 500 to 1000nm. The filling gas of the lamps significantly affects their performance because Ar and Ne lines contaminate different spectral regions. We find differences (up to 88%) in the line intensity of U lines in different lamps from the same batch. We find 8239 isolated lines between 500 and 1700nm that we attribute to U, 3379 of which were not contained in earlier line lists. We suggest using a combination of U-Ne and U-Ar lamps to wavelength-calibrate astronomical spectrographs up to 1um. From 1 to 1.7um, U-Ne shows better properties. The differences in line strength between different HCLs underline the importance of characterizing HCLs in the laboratory. The new 3379 U lines can significantly improve the radial velocity precision of astronomical spectrographs. Description: We provide a U line list obtained from the spectra of a U-Ne hollow cathode lamp from Photron PTY Ltd. using the IFS125HR fourier transform spectrograph located in the Institute for astrophysics Goettingen. The lamp was operated at 12m{AA}. The spectra was recorded using two different setup. The VIS setup covers from 500 to 1000nm. The NIR setup covers from 1000 to 1700nm. The line list contains new wavelength measurement of 8239 unblended lines that we attribute to U. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table5.dat 53 7028 Line list -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 10 F10.4 cm-1 lambdac Line center 12- 15 F4.1 10-3cm-1 e_lambdac Uncertainty on line center 17- 25 F9.4 nm lambdac2 Line center 28- 30 F3.1 pm e_lambdac2 Uncertainty on line center 33- 40 F8.2 --- I Relative line intensity (in au) 43- 45 A3 --- Species Emitting element 48- 53 A6 --- Note Notes (1) -------------------------------------------------------------------------------- Note (1): Notes as follows: R2001 = contained in 2001 ULC = U line candidate 12 = U line candidate only in 12m{AA} spectrum R2001? = U line candidate in R2011 line-list -------------------------------------------------------------------------------- Acknowledgements: Luis Sarmiento, sarmiento.luisfernando(at)gmail.com ================================================================================ (End) Patricia Vannier [CDS] 18-Jun-2018