Context. Absorption lines of H 2 and HD molecules observed at high redshift in the line of sight towards quasars are a test ground to search for variation of the proton-to-electron mass ratio μ. For this purpose, results from astronomical observations are compared with a compilation of molecular data of the highest accuracy, obtained in laboratory studies as well as in first-principles calculations. Aims. A comprehensive line list is compiled for H 2 and HD absorption lines in the Lyman (B 1 Σ u + - X 1 Σ g + ) and Werner (C 1 Π u - X 1 Σ g + ) band systems up to the Lyman cutoff at 912 Å. Molecular parameters listed for each line i are the transition wavelength λ i , the line oscillator strength f i , the radiative damping parameter of the excited state Γ i , and the sensitivity coefficient K i for a variation of the proton-to-electron mass ratio. Methods. The transition wavelengths λ i for the H 2 and HD molecules are determined by a variety of advanced high-precision spectroscopic experiments involving narrowband vacuum ultraviolet lasers, Fourier-transform spectrometers, and synchrotron radiation sources. Results for the line oscillator strengths f i , damping parameters Γ i , and sensitivity coefficients K i are obtained in theoretical quantum chemical calculations. Results. A new list of molecular data is compiled for future analyses of cold clouds of hydrogen absorbers, specifically for studies of μ-variation from quasar data. The list is applied in a refit of quasar absorption spectra of B0642-5038 and J1237+0647 yielding constraints on a variation of the proton-to-electron mass ratio Δμ/μ consistent with previous analyses.
|Number of pages||4|
|Journal||Astronomy and Astrophysics|
|Early online date||7 Feb 2019|
|Publication status||Published - Feb 2019|
- Molecular data
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H2/HD molecular data for quasar spectra analysis
Ubachs, W. (Contributor), Salumbides, E. (Contributor), Murphy, M. T. (Contributor), Abgrall, H. (Contributor) & Roueff, E. (Contributor), Unknown Publisher, 1 Feb 2019
DOI: 10.26093/cds/vizier.36220127, https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/622/A127