A possible spatial and temporal dependence of the fine-structure constant ?=e2/(4 ???0?c) was
investigated. For this purpose, a statistical analysis of fine splitting of [OIII] doublet emission lines in SDSS
(Sloan Digital Sky Survey) quasar spectra is carried out in order to estimate a possible time variation of the
fine-structure constant (?) over cosmological time scales t?1010?yr. After a careful selection of pairs of
lines, the Thong method with a derived analytical expression for the error analysis was applied to compute
the ? variation. We report a new constraint on the variation of the ? based on the analysis of 42 [OIII]
doublets selected from SDSS quasar sample. We find ???/?=(-0.52?0.77)??10-5 over a redshift range
0.16??z??0.80. This result represents a factor of ?14 improvements on the constraint on ???/? based on [OIII
] doublets compared to the published results in the literature. ?? 2010 Springer Science+Business Media
B.V.
