The Excess of JWST Bright Galaxies: a Possible Origin in the Ground State of Dynamical Dark Energy in the light of DESI 2024 Data

TL;DR

This paper investigates whether a dynamical dark energy model with a negative cosmological constant can explain the unexpectedly high abundance of luminous galaxies observed by JWST at high redshifts, aligning with recent DESI data.

Contribution

It introduces a dark energy model with a negative cosmological constant as the ground state of a quintessence field to explain early galaxy formation anomalies.

Findings

Negative {5} 5} models match JWST galaxy luminosity at high z.

Model predicts a steep decline in bright galaxy abundance at z56.

Consistent 55} values with independent cosmological probes.

Abstract

Recent observations by JWST yield a large abundance of luminous galaxies at $z\gtrsim 10$ compared to that expected in the CDM scenario based on extrapolations of the star formation efficiency measured at lower redshifts. While several astrophysical processes can be responsible for such observations, here we explore to what extent such an effect can be rooted in the assumed Dark Energy (DE) sector of the current cosmological model. This is motivated by recent results from different cosmological probes combined with the last data release of the Dark Energy Spectroscopic Instrument (DESI), which indicate a tension in the DE sector of the concordance ${\Lambda}$ CDM model. We have considered the effect of assuming a DE characterized by a negative {\Lambda} as the ground state of a quintessence field on the galaxy luminosity function (LF) at high redshifts. We find that such models naturally affect the galaxy UV luminosities in the redshift range $10 \lesssim z\lesssim 15$ needed to match the JWST observations, and with the value of ${\Omega}_{\Lambda}$=[-0.6,-0.3] remarkably consistent with that required by independent cosmological probes. A sharp prediction of such models is the steep decline of the abundance of bright galaxies in the redshift range $15 \lesssim z\lesssim 16$.