Evolution and mass dependence of UV-to-near-IR color gradients up to <i>z</i> = 2.5 from the Hubble Space Telescope and the James Webb Space Telescope

Aims. We present the redshift evolution of radial color gradients (in rest-frame U − V and V − J ) for galaxies in the range 0.5 &lt; z &lt; 2.5 and investigate their origin and the dependence on stellar mass. Methods. We selected ≈10 200 galaxies with stellar masses M ★ &gt; 10 9.5 M ⊙ from publicly available JWST/NIRCam-selected catalogs. Using 2D Sérsic profile fits to account for point spread function broadening, we performed a spatially resolved spectral energy distribution fitting on HST and JWST/NIRCam photometry to retrieve accurate rest-frame U − V and V − J color gradients within 2 R e, F444W . Results. The generally negative V − J color gradients of star-forming galaxies strongly depend on mass and redshift. For massive star-forming galaxies ( M ★ &gt; 10 10.5 M ⊙ ) at z &gt; 1.5, the V − J colors are ≈0.5 mag redder within the effective radius than outside on average. At all redshifts and throughout the entire stellar mass range, the V − J gradients strongly correlate with global attenuation ( A V ), which suggests that they predominantly trace dust attenuation gradients. Edge-on galaxies are redder and have stronger gradients at all z , although the correlation weakens at higher z . The U − V and V − J color gradients in the quiescent galaxy population, in contrast, are weakly negative (from ≈ − 0.1 to ≈ − 0.2 mag) but significant, and they depend little or not at all on stellar mass, redshift, or axis ratio. The implication is that quiescent galaxies must be largely transparent, with low A V , and their color gradients are mostly attributable to stellar population gradients.