JADES data release 4 – Paper <scp>i</scp> . Sample selection, observing strategy and redshifts of the complete spectroscopic sample

ABSTRACT This paper accompanies Data Release 4 of the James Webb Space Telescope (JWST) Advanced Deep Extragalactic Survey, which presents the full NIRSpec spectroscopy of the survey. We provide spectra of 5190 targets across Great Observatories Origins Deep Survey (GOODS)-North and GOODS-South (including the Hubble Ultra Deep Field), observed with the low-dispersion ($R \approx 30$–300) prism and three medium-resolution ($R \approx 1000$) gratings spanning $0.8 \lt \lambda \lt 5.5~\mu$m; 2654 were also observed with the higher resolution ($R \approx 2700$) G395H grating. The tiered survey design obtained $\gtrsim 20$ h exposures for $\sim 700$ galaxies in the Deep and Ultra Deep tiers, and shallower observations ($\sim 1$–3 h per setting) of $\gt 4400$ galaxies in the Medium tiers. Targets were selected from photometric redshifts or colours, with priority given to rest-UV-selected galaxies at $z \gt 5.7$ and F444W-selected galaxies at $1.5 \lt z \lt 5.7$. We describe the full target selection and present spectroscopic redshifts and success rates. In total, we obtain robust redshifts for 3297 galaxies, including 396 at $z \gt 5.7$ and 2545 at $1.5 \lt z \lt 5.7$. To facilitate uniform analyses, we define ‘gold’ subsamples based on UV- and F444W-selection. Using the parent samples and redshift success rates, we construct rest-UV luminosity functions at $6 \lesssim z \lesssim 9$ from the Medium- and Deep-JWST tiers. Our number densities agree well with previous determinations from both photometric and spectroscopic samples, with modest interloper fractions confirming the reliability of photometric UV-bright galaxy selections at these redshifts.