The rest-frame optical spectrum of JADES-GS-z14-0. Top panel: the final MIRI/LRS 2D spectrum is provided. The corresponding color bar for the measured signal-to-noise ratio per pixel is also shown. JWST/MIRI’s detector plate scale is ﹩0\mathop{.}\limits^{\unicode{x02033}}11\,{{\rm{pixel}}}^{-1}﹩, as shown by the y-axis label. Blue, horizontal lines roughly indicate the wavelength-dependent profiles used for the 1D optimal extraction while the blue, vertical lines indicate the locations for some of the strongest rest-frame optical emission lines. Bottom panel: the final MIRI/LRS 1D spectrum is provided. There are two spectroscopic features that are clearly detected above the noise level (>4σ) in both the 2D and 1D spectra, in addition to the continuum, which is marginally detected (>1σ per wavelength bin at λ_obs ≲ 6 μm). The detection of these rest-frame optical emission lines and their scientific interpretation are the focus of this work, while the rest-frame optical continuum will be discussed and interpreted in a forthcoming manuscript (J. M. Helton et al. 2026, in preparation). The gray, vertical lines indicate the locations of the Balmer continuum limit for JADES-GS-z14-0 and the Paα line for the neighboring foreground galaxy at z = 3.475 (see also Figure 1). The final MIRI/LRS 2D and 1D spectra of JADES-GS-z14-0 are made available in the online journal.

(The data used to create this figure are available in the online article.)

(The data used to create this figure are available.)