We present measurements of the rest-frame ultraviolet luminosity function (UVLF) in three redshift bins over z~5.5-14 from the JWST COSMOS-Web survey. Our samples, selected using the dropout technique in the HST/ACS F814W, JWST/NIRCam F115W, and F150W filters, contain a total of 3099 galaxies spanning a wide luminosity range from faint (M_UV~-19 mag) to bright (M_UV~-22.5 mag). The galaxies are undergoing rapid star formation, with blue stellar populations. Surprisingly, their median UV spectral slope β does not evolve at z>8, suggesting minimal dust, or physical separation of dust and star formation at early epochs. The measured UVLF exhibits an excess at the bright-end (M_UV<-21 mag) compared to pre-JWST empirical results and theoretical predictions of an evolving Schechter function, with the excess beginning at z~9 and becoming increasingly prominent toward z~12. Our analysis suggests that reproducing the observed abundance of UV-bright galaxies at high redshift requires a combination of physical processes, including elevated star formation efficiencies, moderate levels of stochasticity in galaxy luminosities, and minimal dust attenuation.
Physical properties of galaxies and the UV Luminosity Function from z~6 to z~14 in COSMOS-Web / Franco, M., Casey, C.M., Akins, H.B., Ilbert, O., Shuntov, M., Finkelstein, S.L., Paquereau, L., Faisst, A.L., Koekemoer, A.M., Hirschmann, M., Cantarella, S., Drakos, N.E., Wilkins, S.M., Mccracken, H.J., Kartaltepe, J.S., Maraston, C., Abedini, F., Achenbach, M.J., Arango-Toro, R.C., Gentile, F., et al.. - (2025), pp. ---. [10.48550/arXiv.2508.04791]
Physical properties of galaxies and the UV Luminosity Function from z~6 to z~14 in COSMOS-Web
Cantarella, Sebastiano;
2025-01-01
Abstract
We present measurements of the rest-frame ultraviolet luminosity function (UVLF) in three redshift bins over z~5.5-14 from the JWST COSMOS-Web survey. Our samples, selected using the dropout technique in the HST/ACS F814W, JWST/NIRCam F115W, and F150W filters, contain a total of 3099 galaxies spanning a wide luminosity range from faint (M_UV~-19 mag) to bright (M_UV~-22.5 mag). The galaxies are undergoing rapid star formation, with blue stellar populations. Surprisingly, their median UV spectral slope β does not evolve at z>8, suggesting minimal dust, or physical separation of dust and star formation at early epochs. The measured UVLF exhibits an excess at the bright-end (M_UV<-21 mag) compared to pre-JWST empirical results and theoretical predictions of an evolving Schechter function, with the excess beginning at z~9 and becoming increasingly prominent toward z~12. Our analysis suggests that reproducing the observed abundance of UV-bright galaxies at high redshift requires a combination of physical processes, including elevated star formation efficiencies, moderate levels of stochasticity in galaxy luminosities, and minimal dust attenuation.Pubblicazioni consigliate
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