The FENIKS Survey: Spectroscopic Confirmation of Massive Quiescent Galaxies at z ~ 3-5

Jacqueline Antwi-Danso; Casey Papovich; James Esdaile; Themiya Nanayakkara; Karl Glazebrook; Taylor A. Hutchison; Katherine E. Whitaker; Z. Cemile Marsan; Ruben J. Diaz; Danilo Marchesini; Adam Muzzin; Kim-Vy H. Tran; David J. Setton; Yasha Kaushal; Joshua S. Speagle; Justin Cole

paper

The FENIKS Survey: Spectroscopic Confirmation of Massive Quiescent Galaxies at z ~ 3-5

arXiv:2307.09590

Abstract

The measured ages of massive, quiescent galaxies at $z \sim 3 - 4$ imply that massive galaxies quench as early as $z \sim 6$ . While the number of spectroscopic confirmations of quiescent galaxies at $z < 3$ has increased over the years, there are only a handful at $z > 3.5$ . We report spectroscopic redshifts of one secure ( $z = 3.757$ ) and two tentative ( $z = 3.336$ , $z = 4.673$ ) massive ( $lo g (M_{*} / M_{⊙}) > 10.3$ ) quiescent galaxies with 11 hours of Keck/MOSFIRE $K$ -band observations. Our candidates were selected from the FENIKS survey, which uses deep Gemini/Flamingos-2 $K_{b}$ $K_{r}$ imaging optimized for increased sensitivity to the characteristic red colors of galaxies at $z > 3$ with strong Balmer/4000 Å breaks. The rest-frame $U V J$ and $(ug i)_{s}$ colors of 3/4 quiescent candidates are consistent with $1 - 2$ Gyr old stellar populations. This places these galaxies as the oldest objects at these redshifts, and challenges the notion that quiescent galaxies at $z > 3$ are all recently-quenched, "post-starburst" galaxies. Our spectroscopy shows that the other quiescent-galaxy candidate is a broad-line AGN ( $z = 3.594$ ) with strong, redshifted $H β$ +[O III] emission with a velocity offset $> 1000$ km/s, indicative of a powerful outflow. The star-formation history of our highest redshift candidate suggests that its progenitor was already in place by $z \sim 7 - 11$ , reaching $\sim$ 10 $^{11} M_{⊙}$ by $z ≃ 8$ . These observations reveal the limit of what is possible with deep near-infrared photometry and targeted spectroscopy from the ground and demonstrate that secure spectroscopic confirmation of quiescent galaxies at $z > 4$ is only feasible with JWST.

20 pages, 11 figures, submitted to ApJ

The FENIKS Survey: Spectroscopic Confirmation of Massive Quiescent Galaxies at z ~ 3-5

Abstract

Cited by in corpus (5)