Starlight from JWST: Implications for star formation and dark matter models

Abstract

We confront the star formation rate in different dark matter (DM) models with UV luminosity data from JWST up to $z\simeq25$ and legacy data from HST. We find that a transition from a Salpeter population to top-heavy Pop-III stars is likely at $z\simeq10$ and that beyond $z=10-15$ the feedback from supernovae and active galactic nuclei is progressively reduced, so that at $z\simeq25$ the production of stars is almost free from any feedback. We compare fuzzy and warm DM models that suppress small-scale structures with the CDM paradigm, finding that the fuzzy DM mass $> 5.6 \times 10^{-22}{\rm eV}$ and the warm DM mass $> 1.5\, {\rm keV}$ at the 95% CL. The fits of the star formation rate parametrisation do not depend strongly on the DM properties within the allowed range. We find no preference over CDM for enhanced matter perturbations associated with axion miniclusters or primordial black holes. The scale of the enhancement of the power spectrum should be $> 25\,{\rm Mpc}^{-1}$ at the 95% CL, excluding axion miniclusters produced for $m_a < 6.6 \times 10^{-17}\,{\rm eV}$ or heavy primordial black holes that constitute a fraction $f_{\rm PBH} > \max[105 M_\odot/m_{\rm PBH}, 10^{-4} (m_{\rm PBH}/10^4 M_\odot)^{-0.09}]$ of DM.