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Arxiv: Constraints on the variation of the fine-structure constant at 3 < z < 10 with JWST emission-line galaxies Published: 5/15/2024 1:10:16 AM Updated: 1/21/2025 9:59:34 AM

Paper abstract: We present constraints on the spacetime variation of the fine-structureconstant \alpha at redshifts 2.5\le z<9.5 using JWST emission-linegalaxies. The galaxy sample consists of 621 high-quality spectra with strongand narrow [O III] \lambda\lambda4959,5007 doublet emission lines from 578galaxies, including 232 spectra at z>5. The [O III] doublet lines arearguably the best emission lines to probe the variation in \alpha. We divideour sample into six subsamples based on redshift and calculate the relativevariation \Delta\alpha/\alpha for the individual subsamples. The calculated\Delta\alpha/\alpha values are consistent with zero within 1\sigma at allredshifts, suggesting no time variation in \alpha above a level of (1-2)\times10^{-4} (1\sigma) in the past 13.2 billion years. When the wholesample is combined, the constraint is improved to be \Delta\alpha/\alpha =(0.2\pm0.7) \times10^{-4}. We further test the spatial variation in \alphausing four subsamples of galaxies in four different directions on the sky. Themeasured \Delta\alpha/\alpha values are consistent with zero at a 1\sigmalevel of ~ 2\times10^{-4}. While the constraints in this work are not asstringent as those from lower-redshift quasar absorption lines in previousstudies, this work uses an independent tracer and provides the firstconstraints on \Delta\alpha/\alpha at the highest redshifts. With the growingnumber of emission-line galaxies from JWST, we expect to achieve strongerconstraints in the future.