Search for time variation of the fine-structure constant using [OIII] emission lines
A possible spatial and temporal dependence of the fine-structure constant α=e2/(4 πε0ℏc) 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 (α) 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 α variation. We report a new constraint on the variation of the α based on the analysis of 42 [OIII] doublets selected from SDSS quasar sample. We find Δα/α=(-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 Δα/α based on [OIII] doublets compared to the published results in the literature. © 2010 Springer Science+Business Media B.V.