Even redder than we knew: Color and <i>A</i> _V evolution up to <i>z</i> = 2.5 from JWST/NIRCam photometry

Aims. JWST/NIRCam provides rest-frame near-IR photometry of galaxies up to z = 2.5 with exquisite depth and accuracy. This affords us an unprecedented view of the evolution of the UV/optical/near-IR color distribution and its interpretation in terms of the evolving dust attenuation, A V . Methods. We used the value-added data products (photometric redshift, stellar mass, rest-frame U − V and V − J colors, and A V ) provided by the public DAWN JWST Archive. These data products derive from fitting the spectral energy distributions obtained from multiple NIRCam imaging surveys, augmented with preexisting HST imaging data. Our sample consists of a stellar-mass-complete sample of ≈28 000 M ⋆ &gt; 10 9 M ⊙ galaxies in the redshift range 0.5 &lt; z &lt; 2.5. Results. The V − J color distribution of star-forming galaxies evolves strongly, in particular for high-mass galaxies ( M ⋆ &gt; 3 × 10 10 M ⊙ ), which have a pronounced tail of very red galaxies reaching V − J &gt; 2.5 at z &gt; 1.5 that does not exist at z &lt; 1. Such red V − J can only be explained by dust attenuation, with typical values for M ⋆ ≈ 10 11 M ⊙ galaxies in the range A V ≈ 1.5 − 3.5 at z ≈ 2. This redshift evolution went largely unnoticed before. Today, however, photometric redshift estimates for the reddest ( V − J &gt; 2.5), most attenuated galaxies have markedly improved thanks to the new, precise photometry, which is in much better agreement with the 25 available spectroscopic redshifts for such galaxies. The reddest population readily stands out as the independently identified population of galaxies detected at submillimeter wavelengths. Despite the increased attenuation, U − V colors across the entire mass range are slightly bluer at higher z . A well-defined and tight color sequence exists at redshifts 0.5 &lt; z &lt; 2.5 for M ⋆ &gt; 3 × 10 10 M ⊙ quiescent galaxies, in both U − V and V − J , but in V − J it is bluer rather than redder compared to star-forming galaxies. In conclusion, whereas the rest-frame UV-optical color distribution evolves remarkably little from z = 0.5 to z = 2.5, the rest-frame optical/near-IR color distribution evolves strongly, primarily due to a very substantial increase with redshift in dust attenuation for massive galaxies.