Explanation of high redshift luminous galaxies from JWST by early dark energy model

TL;DR

This paper demonstrates that an early dark energy model can simultaneously explain the high abundance of massive high-redshift galaxies observed by JWST and resolve the Hubble tension, aligning cosmological parameters with observations.

Contribution

It introduces an axion-like EDE model combined with a Salpeter IMF to fit JWST galaxy data and cosmological measurements, offering a unified solution to galaxy abundance and Hubble tension.

Findings

JWST data favor a high EDE energy fraction (~0.2)

High Hubble constant (~74.6 km/s/Mpc) consistent with EDE

EDE model explains massive galaxy abundance and Hubble tension

Abstract

Recent observations from the James Webb Space Telescope (JWST) have uncovered massive galaxies at high redshifts, with their abundance significantly surpassing expectations. This finding poses a substantial challenge to both galaxy formation models and our understanding of cosmology. Additionally, discrepancies between the Hubble parameter inferred from high-redshift cosmic microwave background (CMB) observations and those derived from low-redshift distance ladder methods have led to what is known as the ``Hubble tension''. Among the most promising solutions to this tension are Early Dark Energy (EDE) models. In this study, we employ an axion-like EDE model in conjunction with a universal Salpeter initial mass function to fit the luminosity function derived from JWST data, as well as other cosmological probes, including the CMB, baryon acoustic oscillations (BAO), and the SH0ES local distance ladder. Our findings indicate that JWST observations favor a high energy fraction of EDE, $ f_\text{EDE} \sim 0.2 \pm 0.03 $, and a high Hubble constant value of $ H_0 \sim 74.6 \pm 1.2 $ km/s/Mpc, even in the absence of SH0ES data. This suggests that EDE not only addresses the $ H_0 $ tension but also provides a compelling explanation for the observed abundance of massive galaxies identified by JWST.