The ratio of the C IVlambdalambda1548,1550 rest-wavelengths from high-redshift QSO absorption lines.

Patrick Petitjean (1, 2) , B. Aracil (1, 3)

1 IAP - Institut d'Astrophysique de Paris
2 LERMA - Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique
3 Department of Astronomy, University of Massachusetts

We use very high quality VLT-UVES quasar spectra obtained in the course of the ESO Large Programme "Cosmic evolution of the Intergalactic Medium", to show that the ratio of the C IV doublet rest-wavelengths published in the literature and widely used is not consistent with high-redshift observations. From the analysis of 106 C IV systems we obtain: lambda₂/ lambda₁ = 1.00166228±0.013×10^-6. A similar analysis on 28 Si IV systems shows that the observed ratio is consistent with the well known Si IV lambdalambda 1393,1402 wavelengths. Using Si IV lines to calibrate the C IV lines in 11 systems, we find lambda_1,2=1548.2049 and 1550.7885±0.0012 Å which is consistent with the Griesmann & Kling (2000) laboratory wavelengths. The precision on the doublet ratio is better because of the large number of C IV systems available for the measurement. This shows that it is possible to perform atomic physics measurements using high redshift astrophysical data.

Domaines: Astrophysique [astro-ph]

Patrick Petitjean, B. Aracil. The ratio of the C IVlambdalambda1548,1550 rest-wavelengths from high-redshift QSO absorption lines.. Astronomy and Astrophysics - A&A, 2004, 422, pp.523-526. ⟨10.1051/0004-6361:20041030⟩. ⟨hal-03733432⟩