The Infrared Spectrum of Uranium Hollow Cathode Lamps from 850 nm to 4000 nm: Wavenumbers and Line Identifications from Fourier Transform Spectra

TL;DR

This paper presents new measurements of uranium emission lines in the near-infrared spectrum, providing a comprehensive line list to improve wavelength calibration for high-resolution NIR spectrographs.

Contribution

It offers an extensive, accurate line list of uranium spectral lines in the NIR range, enhancing calibration capabilities over previous thorium-based references.

Findings

Six times more calibration lines than thorium in NIR range

Provides line identifications for 10,100 uranium lines

Enables high-precision wavelength calibration with uranium lamps

Abstract

We provide new measurements of wavenumbers and line identifications of 10 100 UI and UII near-infrared (NIR) emission lines between 2500 cm-1 and 12 000 cm-1 (4000 nm to 850 nm) using archival FTS spectra from the National Solar Observatory (NSO). This line list includes isolated uranium lines in the Y, J, H, K, and L bands (0.9 {\mu}m to 1.1 {\mu}m, 1.2 {\mu}m to 1.35 {\mu}m, 1.5 {\mu}m to 1.65 {\mu}m, 2.0 {\mu}m to 2.4 {\mu}m, and 3.0 {\mu}m to 4.0 {\mu}m, respectively), and provides six times as many calibration lines as thorium in the NIR spectral range. The line lists we provide enable inexpensive, commercially-available uranium hollow-cathode lamps to be used for high-precision wavelength calibration of existing and future high-resolution NIR spectrographs.