Even redder than we knew: color and $A_{\mathrm{V}}$ evolution up to $z=2.5$ from JWST/NIRCam photometry

Abstract

JWST/NIRCam provides rest-frame near-IR photometry of galaxies up to $z=2.5$ with exquisite depth and accuracy. This affords an unprecedented view of the evolution of the UV-optical-near-IR color distribution and its interpretation in terms of the evolving dust attenuation, $A_{\mathrm{V}}$. We use the value-added data products (photometric redshift, stellar mass, rest-frame $U-V$ and $V-J$ colors, and $A_{\mathrm{V}}$) provided by the public DAWN JWST Archive. This data product derives from fitting the spectral energy distributions obtained from multiple NIRCam imaging surveys, augmented with pre-existing HST imaging data. Our sample consists of a stellar mass complete sample of $\approx 28,000$ $M_{\star }>10^9{M}_{\odot }$ galaxies in the redshift range $0.5<z<2.5$. The $V-J$ color distribution of star-forming galaxies evolves strongly, in particular for high-mass galaxies ($M_{\star }>3\times 10^{10}{M}_{\odot }$), which have a pronounced tail of very red galaxies reaching $V-J>2.5$ at $z>1.5$ that does not exist at $z<1$. Such red $V-J$ can only be explained by dust attenuation, with typical values for $M_{\star }\approx 10^{11}{M}_{\odot }$ galaxies in the range $A_{\mathrm{V}}\approx 1.5-3.5$ at $z\approx 2$. This redshift evolution went largely unnoticed before because the photometric redshift estimates for the reddest ($V-J>2.5$), most attenuated galaxies has markedly improved thanks to the new, precise photometry. Despite the increased attenuation, $U-V$ colors across the entire mass range are slightly bluer at higher $z$. 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. (Abbr.)

Accepted for publication in A&A. This second version has minor corrections to adhere to A&A style