COSMOS-Web: Galaxy Size and Surface Brightness Evolution at Rest Frame 1.22 μm Since z=3

We present the evolution of galaxy size and surface brightness in the rest-frame J band (1.22 mu m), tracing the stellar mass distribution, over 0.5 <= z <= 3, using a sample of 15,420 galaxies with stellar masses M-star = 10(10)-10(11.5)M(circle dot) from the JWST COSMOS-Web survey. The rest-frame J-band effective radius (R-e,R-J) is obtained from previous measurements and mapped from the available JWST/NIRCam filters, while the surface brightness (mu(J)) is corrected for dust extinction and cosmological dimming. At a characteristic mass of M-star = 5 & times; 10(10)M(circle dot), star-forming galaxies (SFGs) exhibit a size evolution of R-e,R-J proportional to (1 + z)(beta) with beta = -0.92 +/- 0.04, falling between previously reported shallower and steeper measurements. Quiescent galaxies evolve more rapidly, with beta = -1.34 +/- 0.05, consistent with earlier studies. Among SFGs, lower-mass systems (10(10)-10(10.5)M(circle dot)) show slower (beta = -0.66 +/- 0.02) size evolution compared to their higher-mass counterparts. Furthermore, the surface brightness brightens toward higher redshifts, scaling as mu J proportional to - 2.5 log ( 1 + z ) gamma . We find gamma = 3.07 +/- 0.08 for SFGs and gamma = 3.70 +/- 0.08 for quiescent galaxies. We also find that massive SFGs (M-star > 10(10.5) M-circle dot) exhibit similar mu(J) values at fixed redshift, independent of mass. Finally, we demonstrate that the observed surface brightness evolution is driven by the combined evolution of galaxy luminosity and size.