Age of massive galaxies at redshift 8
M. Lopez-Corredoira, F. Melia, J.-J. Wei, C.-Y. Gao

TL;DR
Analysis of JWST data suggests the existence of massive galaxies at redshift 8 that appear older than the universe itself in standard cosmology, challenging current models and hinting at possible new physics.
Contribution
This study provides a detailed stellar population analysis of high-redshift galaxies, highlighting a significant tension with standard cosmological predictions.
Findings
Galaxies observed at z~8 are inferred to be 0.9-2.4 Gyr old.
Standard cosmology predicts these galaxies should be younger than 290 Myr.
Statistical analysis shows a less than 0.03% probability of such old ages under ΛCDM.
Abstract
Recent James Webb Space Telescope (JWST) data analyses have shown that massive red galaxies existed at redshifts , a discovery that is difficult to understand in the context of standard cosmology (CDM). 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 AGN component do not significantly improve the fits. These galaxies are being viewed at very high redshifts, with an average , when the CDM Universe was only Myr old. This result conflicts with the inferred ages of these galaxies, however, which were…
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Taxonomy
TopicsAstronomy and Astrophysical Research · Galaxies: Formation, Evolution, Phenomena · Scientific Research and Discoveries
