2026ApJ...998..229X

Using JWST observations in CANDELS fields, we measure the half-light radius (r_e,light) and half-mass-radius (r_e,mass) for 14,333 galaxies with stellar masses M_* > 10⁹M_⊙ _at redshifts 0.2 < z < 2.5. To investigate the difference between r_e,light and r_e,mass, we find that r_e,light is larger than r_e,mass for both quiescent galaxies (QGs) and star-forming galaxies (SFGs). Moreover, the difference between these two radii is clearly correlated with galaxy stellar mass, r_e,light, and the rest-frame U - V color. When examining the evolution of the r_e,mass/r_e,light ratio, we observe a significant increase for SFGs at z > 1.7. In contrast, no clear increase is observed for QGs at z > 1, though a slight decreasing trend is seen between 0.2 < z < 1.0. By fitting a linear relationship between galaxy size and stellar mass, we find that the slope for r_e,light is ∼0.1-0.3 dex larger than that for r_e,mass. In terms of galaxy size evolution at a fixed stellar mass, the r_e,mass of QGs increases by a factor of ∼3-5 from z ∼ 2.5 to z ∼ 0.2. In contrast, the r_e,mass of SFGs increases by a factor of approximately 2 over the same redshift range, with this growth trend closely following that of their r_e,light. These results indicate that previous insights into galaxy evolution based on r_e,light remain valid when considering r_e,mass, although the specific slopes show some variations.