JWST high redshift galaxy observations have a strong tension with Planck CMB measurements

Abstract

JWST high redshift galaxy observations predict a higher star formation efficiency than the standard cosmology does, which poses a new tension to $\Lambda$CDM. We find that the situation is worse than expected. The true situation is that the Planck CMB measurement has a strong tension with JWST high redshift galaxy observations. Specifically, we make a trial to alleviate this tension by considering alternative cosmological models including dark matter-baryon interaction, $f(R)$ gravity and dynamical dark energy. Within current cosmological constraints from Planck-2018 CMB data, we find that these models all fail to explain such a large tension. A possible scenario to escape from cosmological constraints is the extended Press-Schechter formalism, where we consider the local environmental effect on the early formation of massive galaxies. Interestingly, we find that an appropriate value of nonlinear environmental overdensity of a high redshift halo can well explain this tension.

Comments: 8 pages, 3 figs. Non-standard cosmolgies hardly resolve the tension between JWST high-z galaxy observations and Planck CMB data