James Webb Space Telescope Feed Post

Searching for Emission Lines at z > 11: The Role of Damped Lyman-a and Hints About the Escape of Ionizing Photons (JADES-GS-z13-0)

2D and 1D NIRSpec PRISM/CLEAR spectra for JADES-GS-z13-0, from the combined spectra from observations under PID 1210 as described in Curtis-Lake et al. (2023) and the new, deeper observations under PID 3215. In each panel, we plot the 2D spectrum underneath the sigma-clipped 1D spectrum. For the 1D spectrum, plotted in blue, we also plot uncertainties in light grey. We plot the positions of UV and optical emission lines with dashed lines at the fiducial redshifts estimated for each source. In an insert, we show the 2''×2'' JADES F444W+F200W+F090W RGB cutout with the MSA slitlets used for PID 3215 overplotted. Abstract: We describe new ultra-deep James Webb Space Telescope (JWST) NIRSpec PRISM and grating spectra for the galaxies JADES-GS-z11-0 (zspec=11.122+0.005-0.003) and JADES-GS-z13-0 (zspec=13.20+0.03-0.04), the most distant spectroscopically-confirmed galaxy discovered in the first year of JWST observations. The extraordinary depth of these observations (75 hours and 56 hours, respectively) provides a unique opportunity to explore the redshifts, stellar properties, UV magnitudes, and slopes for these two sources. For JADES-GS-z11-0, we find evidence for multiple emission lines, including [OII]3726,3729 and [NeIII]3869, resulting in a spectroscopic redshift we determine with 94% confidence. At this spectroscopic redshift, the Lyman-a break in JADES-GS-z11-0 can be fit with a damped Lyman-a absorber with log(NHI/cm-2)=22.42+0.093-0.120. We present stringent upper limits on the emission line fluxes and line equivalent widths for JADES-GS-z13-0. These results demonstrate how neutral hydrogen fraction and Lyman-damping wings may impact the recovery of spectroscopic redshifts for sources like these, providing insight into the overprediction of the photometric redshifts seen for distant galaxies observed with JWST. In addition, we analyze updated NIRCam photometry to calculate the morphological properties of these resolved sources, and find a secondary source 0.3'' south of JADES-GS-z11-0 at a similar photometric redshift, hinting at how galaxies grow through interactions in the early Universe.