Age of Massive Galaxies at Redshift 8

Recent James Webb Space Telescope data analyses have shown that massive red galaxies existed at redshifts z ≳ 6, a discovery that is difficult to understand in the context of standard cosmology (ΛCDM). Here, we analyze these observations more deeply, by fitting a stellar population model to the opti...

Full description

Saved in:
Bibliographic Details
Published in:The Astrophysical journal 2024-07, Vol.970 (1), p.63
Main Authors: López-Corredoira, M., Melia, F., Wei, J.-J., Gao, C.-Y.
Format: Article
Language:English
Subjects:
Active galactic nuclei
Astronomical models
Astrophysics
Confidence intervals
Cosmology
Data analysis
Extinction
Galaxies
High-redshift galaxies
Infrared analysis
Infrared photometry
Observational cosmology
Red shift
Space telescopes
Star & galaxy formation
Star formation
Statistical analysis
Stellar models
Stellar populations
Universe
Citations: Items that this one cites
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Recent James Webb Space Telescope data analyses have shown that massive red galaxies existed at redshifts z ≳ 6, a discovery that is difficult to understand in the context of standard cosmology (ΛCDM). Here, we analyze these observations more deeply, by fitting a stellar population model to the optical and near-infrared photometric data. These fits include a main stellar population in addition to a residual younger population and with the same extinction for both (a lower extinction for the younger population is unphysical). Extra stellar populations or the inclusion of an active galactic nucleus component do not significantly improve the fits. These galaxies are being viewed at very high redshifts, with an average 〈 z 〉 ≈ 8.2, when the ΛCDM Universe was only ≈600 Myr old. This result conflicts with the inferred ages of these galaxies, however, which were on average between 0.9 and 2.4 Gyr old within a 95% confidence level. Given the sequence of star formation and galaxy assembly in the standard model, these galaxies should instead be even younger than 290 Myr on average, for which our analysis assigns a probability of only
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ad4f86