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Published online by Cambridge University Press: 13 February 2024
We present the first results from JWST/NIRSPEC spectroscopy of massive quiescent galaxy candidates at 3<z<4 to complete the spectroscopic survey of Schreiber et al. 2018. In the first six objects targeted (all of which were too faint to secure spectroscopic identifications from the ground) they all are confirmed as yet more massive quiescent galaxies at 3<z<4. The JWST spectra are high signal-to-noise and unambiguous. Most of them have ages of a few hundred Myr from stellar population fits to the spectra and about 1/3 show sign of AGN emission lines. One extraordinary object of stellar mass 1.6×1011 M⊙ shows a red spectrum with evidence of a 4000Å break and an age of ≳ 1Gyr at z=3.2 and forming at z>6.