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We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminouscandidate $z>10$ Lyman break galaxy in the GOODS-North field with$M_{UV}=-21.5$. We derive a redshift of $z=10.603$ (lower than previousdeterminations) based on multiple emission lines in our low and mediumresolution spectra over $0.8-5.3 \mu$m. We significantly detect the continuumand measure a blue rest-UV spectral slope of $\beta=-2.4$. Remarkably, we seespatially-extended Lyman-$\alpha$ in emission (despite the highly-neutral IGMexpected at this early epoch), offset 555 km s$^{-1}$ redward of the systemicredshift. From our measurements of collisionally-excited lines of both low- andhigh-ionization (including [O II]$\lambda3727$, [Ne III]$\lambda 3869$ and CIII]$\lambda1909$) we infer a high ionization parameter ($\log U\sim -2$). Wedetect the rarely-seen N IV]$\lambda1486$ and N III]$\lambda1748$ lines in bothour low and medium resolution spectra, with other high ionization lines seen inthe low resolution spectrum such as He II (blended with O III]) and C IV (witha possible P-Cygni profile). Based on the observed rest-UV line ratios, wecannot conclusively rule out photoionization from AGN, although the high CIII]/He II and N III]/He II ratios are compatible with a star-formationexplanation. If the observed emission lines are powered by star formation, thenthe strong N III]$\lambda1748$ observed may imply an unusually high $N/O$abundance. Balmer emission lines (H$\gamma$, H$\delta$) are also detected, andif powered by star formation rather than an AGN we infer a star formation rateof $\sim 20-30 M_{\odot} yr^{-1}$ (depending on the IMF) and low dustattenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkablegalaxy with extreme properties seen 430 Myr after the Big Bang.

JADES NIRSpec Spectroscopy of GN-z11: Lyman-$\alpha$ emission and possible enhanced nitrogen abundance in a $z=10.60$ luminous galaxy