High-Redshift Galaxies from Early JWST Observations: Constraints on Dark Energy Models

Early observations with JWST have led to the discovery of an unexpected large density (stellar mass density ${\rho }_{\ast }\approx {10}^6{M}_{\odot }Mp{c}^{-3}$) of massive galaxies (stellar masses $M_{\ast }\ge {10}^{10.5}{M}_{\odot }$) at extremely high redshifts $z\approx 10$. We show that - under the most conservative assumptions, and independently of the baryon physics involved in galaxy formation - such abundance is not only in tension with the standard $\mathrm{\Lambda }$CDM cosmology, but provides extremely tight constraints on the expansion history of the Universe and on the growth factors corresponding to a wide class of Dark Energy (DE) models. The constraints we derive rule out with high ($>2\sigma$) confidence level a major portion of the parameter space of Dynamical DE models allowed (or even favoured) by existing cosmological probes.