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 ( ${R}_{{{M}}_{\star }}$ ) derived with multicolor light profiles from CANDELS Hubble Space Telescope imaging. In general agreement with previous work, we find that R _NIR and ${R}_{{{M}}_{\star }}$ are up to 40% smaller than the rest-frame optical half-light radius R _opt. The agreement between R _NIR and ${R}_{{{M}}_{\star }}$ 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 ${R}_{{{M}}_{\star },3{\rm{D}}}$ , 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, ${R}_{{{M}}_{\star }}$ , and ${R}_{{{M}}_{\star },3{\rm{D}}}$ . The slope is significantly flatter for ${R}_{{{M}}_{\star }}$ and ${R}_{{{M}}_{\star },3{\rm{D}}}$ compared to R _opt, mostly due to downward shifts in size for massive star-forming galaxies, while ${R}_{{{M}}_{\star }}$ and ${R}_{{{M}}_{\star },3{\rm{D}}}$ 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, ${R}_{{{M}}_{\star }}$ , and ${R}_{{{M}}_{\star },3{\rm{D}}}$ . 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.