A merging pair of massive quiescent galaxies at <i>z</i> = 3.44 in the Cosmic Vine

We report the spectroscopic confirmation of a merging pair of massive quiescent galaxies at z = 3.44. Using JWST observations, we confirm that the two galaxies lie at a projected separation of 4.5 kpc with a velocity offset of ∼680 km s −1 ( δ z ∼ 0.01). The pair resides in the core of a known rich overdensity of galaxies, dubbed the “Cosmic Vine”. For both pair members, modeling of the spectral energy distributions and faint rest-frame optical emission lines indicate high stellar masses (log( M ⋆ / M ⊙ ) ∼ 10.9) and suppressed star formation (log(sSFR/yr −1 ) &lt; −10), more than an order of magnitude below the level of the star formation main sequence at this…