Constraints on the variation of the fine-structure constant at 3<z<10 with JWST emission-line galaxies

We present constraints on the spacetime variation of the fine-structure constant $\alpha$ at redshifts $3

The galaxy sample consists of 572 high-quality spectra with strong and narrow [O III] $\lambda\lambda$4959,5007 doublet emission lines from 522 galaxies, including 267 spectra at $z>5$.

The [O III] doublet lines are arguably the best emission lines to probe the variation in $\alpha$.

We divide our sample into 5 subsamples based on redshift and calculate the relative variation $\Delta\alpha/\alpha$ for the individual subsamples.

The calculated $\Delta\alpha/\alpha$ values are consistent with zero within $1\sigma$ at all redshifts, 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 whole sample is combined, the constraint is improved to be $\Delta\alpha/\alpha = (0.4\pm0.7) \times10^{-4}$.

We further test the spatial variation in $\alpha$ using four subsamples of galaxies in four different directions on the sky.

The measured $\Delta\alpha/\alpha$ values are consistent with zero at a $1\sigma$ level of $\sim10^{-4}$.

While the constraints in this work are not as stringent as those from lower-redshift quasar absorption lines in previous studies, this work uses an independent tracer and provides the first constraints on $\Delta\alpha/\alpha$ at the highest redshifts.

Our analyses also indicate that the relative wavelength calibration of the JWST spectra is robust.

With the growing number of emission-line galaxies from JWST, we expect to achieve stronger constraints in the future.

;Comment: 9 pages, 6 figures, submitted to ApJ