Fitting the spectrum of the z = 9.44 galaxy jades-3215-265801. Left: 2D posteriors for $x_{\mathrm{H}\mathrm{I}},D_b,E{W}_{\mathrm{Ly}\alpha ,\mathrm{emit}},E{W}_{\mathrm{Ly}\alpha ,\mathrm{obs}},\mathrm{\Delta }v,N_{\mathrm{H}\mathrm{I}},f_{\mathrm{cov}}$. Red contours show the posteriors including f_cov and black contours show the posteriors fixing f_cov = 1. We see the IGM and Lyα parameters are not sensitive to fixing f_cov, though allowing f_cov < 1 will allow higher N_H I solutions. Right: Observed spectrum and uncertainty (black line and shaded region) compared with the best-fit ‘observed’ (including absorption by IGM and DLAs), ‘intrinsic’ models (emission only in an ionized IGM), ‘intrinsic+DLA’ models (emission + DLA absorption in an ionized IGM) plotted in red, blue and green respectively. Lines show the median of the models, shaded regions show the 68% range. This spectrum is consistent with a highly neutral IGM (${\overline{x}}_{\mathrm{H}\mathrm{I}}>0.74(1\sigma )$) at z = 9.44.