2025/09/23 by Xuejian Shen, Oliver Zier, Shen, Xuejian +11 · 1 voice · 2 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #COSMIC cancer database #Cosmology #Cosmology and Gravitation Theories #Dark matter #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy formation and evolution #Redshift #Star formation #Structure formation #Universe
paper · pdf · open access · doi:10.1093/mnras/stag1227
published in Monthly Notices of the Royal Astronomical Society 550(2) (Oxford University Press)
openalex publication_date 2026/06/26 · openalex created_date 2026/06/27 · openalex updated_date 2026/08/05
ABSTRACT Early James Webb Space Telescope (JWST) observations have revealed a high-redshift universe more vibrant than predicted by canonical galaxy-formation models within Lambda cold dark matter (ΛCDM), showing an excess of ultraviolet(UV)-bright, massive, and morphologically mature galaxies. Departures from ΛCDM prior to recombination can imprint signatures on non-linear structure formation at high redshift. In this paper, we investigate one such scenario – Early Dark Energy, originally proposed to resolve the Hubble tension – and its implications for these high-redshift challenges. We present the first large-scale cosmological hydrodynamic simulations of these models. Modifications to the pre-recombination expansion history accelerate early structure formation and produce UV luminosity and stellar mass functions in excellent agreement with JWST measurements, requiring essentially no additional calibrations. Predictions converge to ΛCDM at lower redshifts (z \lesssim 3), thereby preserving all successes of ΛCDM. This model also accelerates the emergence of stellar and gaseous discs, increasing their number densities by ∼ 0.5 dex at z≃ 6–7, primarily due to the higher abundance of massive galaxies. Taken together, these results demonstrate how early-universe physics can simultaneously reconcile multiple high-redshift challenges and the Hubble tension while retaining the core achievements of ΛCDM. This opens a pathway to constraining a broad class of beyond-ΛCDM models with forthcoming observations.