ACCURATE LABORATORY WAVELENGTHS OF THE 1910 angstrom Ti II RESONANCE TRANSITIONS RELEVANT TO STUDIES OF POSSIBLE VARIATIONS OF THE FINE-STRUCTURE CONSTANT

作者：Ruffoni M P^*; Pickering J C

来源：Astrophysical Journal, 2010, 725(1): 424-429.

DOI：10.1088/0004-637X/725/1/424

• atomic data
• line: profiles
• methods: laboratory
• quasars: absorption lines
• techniques: spectroscopic
• ultraviolet: general

In recent years, the analysis of absorption lines in quasi-stellar object (QSO) spectra, using the many-multiplet (MM) method, has provided evidence for space-time variations in the fine-structure constant, alpha. Future studies aim to reduce systematic errors in these measurements by considering a greater number of transitions, but this is only possible for lines where high-precision laboratory standards exist. Two transitions of high importance for future MM analyses, but which currently lack accurately measured wavelengths, are the Ti II transitions observed at 1910 angstrom. We report accurate measurements of these transitions by high-resolution Fourier transform spectroscopy, giving line wavenumbers of (52,329.889 +/- 0.001) cm(-1) and (52,339.240 +/- 0.001) cm(-1). Lines from other important Ti II, Mg I, Mg II, and Zn II transitions were measured simultaneously, minimizing their relative wavenumber uncertainties, and permitting the newly measured 1910 angstrom Ti II line wavenumbers to be linked directly to lines from other studies.

• 出版日期2010-12