Stellar Half-mass Radii of 0.5 z < 2.3 Galaxies: Comparison with JWST/NIRCam Half-light Radii

Abstract

We use CEERS JWST/NIRCam imaging to measure rest-frame near-IR light profiles of 435 M ⋆ > 1010 M ⊙ galaxies in the redshift range of 0.5 < z < 2.3. We compare the resulting rest-frame 1.5–2 μm half-light radii (R NIR) with stellar half-mass radii ( RM⋆ ) derived with multicolor light profiles from CANDELS Hubble Space Telescope imaging. In general agreement with previous work, we find that R NIR and RM⋆ are up to 40% smaller than the rest-frame optical half-light radius R opt. The agreement between R NIR and RM⋆ is excellent, with a negligible systematic offset (<0.03 dex) up to z = 2 for quiescent galaxies and up to z = 1.5 for star-forming galaxies. We also deproject the profiles to estimate RM⋆,3D , the radius of a sphere containing 50% of the stellar mass. We present the R−M ⋆ distribution of galaxies at 0.5 < z < 1.5, comparing R opt, RM⋆ , and RM⋆,3D . The slope is significantly flatter for RM⋆ and RM⋆,3D compared to R opt, mostly due to downward shifts in size for massive star-forming galaxies, while RM⋆ and RM⋆,3D do not show markedly different trends. Finally, we show rapid evolution of the size (R ∝ (1 + z)−1.7±0.1) of massive (M ⋆ > 1011 M ⊙) quiescent galaxies between z = 0.5 and z = 2.3, again comparing R opt, RM⋆ , and RM⋆,3D . We conclude that the main tenets of the evolution of the size narrative established over the past 20 yr, based on rest-frame optical light profile analysis, still hold in the era of JWST/NIRCam observations in the rest-frame near-IR.