JADES: Rest-frame UV-to-NIR Size Evolution of Massive Quiescent Galaxies from Redshift; z; = 5 to; z; = 0.5
Journal Article
Overview
abstract
Abstract; ; We present the UV-to-near-IR (NIR) size evolution of a sample of 161 quiescent galaxies with; M; *; > 10; 10; M; ⊙; over 0.5 < ; z; < 5. With deep multiband NIRCam images in GOODS-South from JADES, we measure the effective radii (; R; ; e; ; ) of the galaxies at rest-frame 0.3, 0.5, and 1; μ; m. On average, we find that quiescent galaxies are 45% (15%) more compact at rest-frame 1; μ; m than they are at 0.3; μ; m (0.5; μ; m). Regardless of wavelengths, the; R; ; e; ; of quiescent galaxies strongly evolves with redshift, and this evolution depends on stellar mass. For lower-mass quiescent galaxies with; M; *; = 10; 10; –10; 10.6; M; ⊙; , the evolution follows; R; ; e; ; ∝ (1 + ; z; ); −1.1; , whereas it becomes steeper, following; R; ; e; ; ∝ (1 + ; z; ); −1.7; , for higher-mass quiescent galaxies with; M; *; > 10; 10.6; M; ⊙; . To constrain the physical mechanisms driving the apparent size evolution, we study the relationship between; R; ; e; ; and the formation redshift (; z; form; ) of quiescent galaxies. For lower-mass quiescent galaxies, this relationship is broadly consistent with; ; ; ; ; ; ; ; R; ; ; e; ; ; ∝; ; ; (; 1; +; ; ; z; ; ; form; ; ; ); ; ; −; 1; ; ; ; ; , in line with the expectation of the progenitor effect. For higher-mass quiescent galaxies, the relationship between; R; ; e; ; and; z; form; depends on stellar age. Older quiescent galaxies have a steeper relationship between; R; ; e; ; and; z; form; than that expected from the progenitor effect alone, suggesting that mergers and/or post-quenching continuous gas accretion drive additional size growth in very massive systems. We find that the; z; > 3 quiescent galaxies in our sample are very compact, with mass surface densities Σ; ; e; ; ≳ 10; 10; M; ⊙; kpc; −2; , and their; R; ; e; ; are possibly even smaller than anticipated from the size evolution measured for lower-redshift quiescent galaxies. Finally, we take a close look at the structure of GS-9209, one of the earliest confirmed massive quiescent galaxies at; z; spec; ∼ 4.7. From UV to NIR, GS-9209 becomes increasingly compact, and its light profile becomes more spheroidal, showing that the color gradient is already present in this earliest massive quiescent galaxy.;
