Probing the time-variation of the fine-structure constant: Results based on Si IV doublets from a UVES sample^*

¹ IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007, India e-mail: hcverma@iucaa.ernet.in
² Institut d'Astrophysique de Paris – CNRS, 98bis Boulevard Arago, 75014 Paris, France
³ LERMA, Observatoire de Paris, 61 Rue de l'Observatoire, 75014 Paris, France
⁴ Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003-9305, USA

Received: 29 April 2004
Accepted: 9 September 2004

Abstract

We report a new constraint on the variation of the fine-structure constant based on the analysis of 15 Si iv doublets selected from a ESO-UVES sample. We find  =  over a redshift range of which is consistent with no variation in α. This result represents a factor of three improvement on the constraint on   based on Si iv doublets compared to the published results in the literature. The alkali doublet method used here avoids the implicit assumptions used in the many-multiplet method that chemical and ionization inhomogeneities are negligible and isotopic abundances are close to the terrestrial value.