EDP Sciences
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Volume 430, Number 1, January IV 2005
Page(s) 47 - 58
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:20041186

A&A 430, 47-58 (2005)
DOI: 10.1051/0004-6361:20041186

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

H. Chand1, P. Petitjean2, 3, R. Srianand1 and B. Aracil2, 4

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)

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 $\Delta\alpha/\alpha$ =  ${ (+0.15\pm0.43)\times10^{-5}}$ over a redshift range of ${ 1.59\le z\le 2.92}$ which is consistent with no variation in $\alpha$. This result represents a factor of three improvement on the constraint on $\Delta\alpha/\alpha$  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.

Key words: quasars: absorption lines -- cosmology: observations

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