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.
<Astron. Astrophys. 618, A118 (2018)>
=2018A&A...618A.118S 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 12mÅ. 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:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table5.dat 53 7028 Line list
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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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)
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Note (1): Notes as follows:
R2001 = contained in 2001
ULC = U line candidate
12 = U line candidate only in 12mÅ spectrum
R2001? = U line candidate in R2011 line-list
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Acknowledgements:
Luis Sarmiento, sarmiento.luisfernando(at)gmail.com
(End) Patricia Vannier [CDS] 18-Jun-2018