On the stunning abundance of super-early, luminous galaxies revealed by JWST

ABSTRACT The earliest JWST observations have revealed an unexpected abundance of super-early (z 10), massive (M_*\, 10⁹ M) galaxies at the bright-end (MUV ≈ −21) of the ultraviolet luminosity function (UV LF). We present a minimal physical model that explains the observed galaxy abundance at z = 10–14. The model primarily combines (i) the halo mass function, with (ii) an obscured star formation fraction prescription that is consistent with findings of the ALMA REBELS dusty galaxy survey. It has been successfully tested on well-known UV LFs up to z = 7. We argue that the weak evolution from z = 7 to z ≈ 14 of the LF bright-end can arise from a conspiracy between a decreasing dust attenuation, making galaxies brighter, that almost exactly compensates for the increasing shortage of their host halos. Our minimal model naturally reproduces the z = 10–14 LF if galaxies at z. 5ex\, \, \, \, 11 contain a negligible amounts of dust. We speculate that dust could have been efficiently ejected during the very first phases of galaxy build-up.