Source: the original JWST massive-galaxy candidates and the baryon test

Labbé et al., Nature 2023 identified six photometric candidates with inferred stellar masses above 10 billion solar masses at z=7.4–9.1, including one with a possible mass of ~100 billion solar masses. The paper expressly conditioned its high stellar-mass-density implication on spectroscopy. These are masses inferred from stellar-population models fitted to light, not direct weights.

Boylan-Kolchin, Nature Astronomy 2023 compared the inferred stellar-mass density with the maximum baryons in ΛCDM dark-matter halos. The then-extreme candidates required conversion efficiencies near 100% (or still implausibly high with statistical uncertainty). The comparison is a conditional stress test of candidate photometric masses, not proof that ΛCDM had failed. Both authors explicitly flag uncertain stellar-mass inference/confirmation.

Kocevski et al. 2023 spectroscopically identified CEERS 3210 at z=5.624 as a dust-obscured broad-line AGN after it had been targeted as a z>8 candidate; contemporary de Graaff's analysis of this source identifies it as one of Labbé’s z≈8.3 candidates. Do not conflate this individual redshift correction with a uniform downward revision of the entire sample. Where exactly each other candidate now sits remains to be mapped.

Follow the evidence at the galaxy question and the new CEERS census.