Predictions for the abundance of high-redshift galaxies in a fuzzy dark matter universe

During the last decades, rapid progress has been made in measurements of the rest-frame ultraviolet (UV) luminosity function (LF) for high-redshift galaxies (z >= 6). The faint-end of the galaxy LF at these redshifts provides powerful constraints on different dark matter (DM) models that suppress small-scale structure formation. In this work we perform full hydrodynamical cosmological simulations of galaxy formation using an alternative DM model composed of extremely light bosonic particles (m similar to 10(-22) eV), also known as fuzzy dark matter (FDM), and examine the predictions for the galaxy stellar mass function and LF at z >= 6 for a range of FDM masses. We find that for FDM models with bosonic mass m= 5x10(-22) eV, the number density of galaxies with stellar mass is suppressed by at z =9, at z =5, and the UV LFs within magnitude range of -16 < M-UV < -14 is suppressed by at z= 9, at z= 5 comparing to the cold dark matter counterpart simulation. Comparing our predictions with current measurements of the faint-end LFs (-18 <= M-UV <= -14), we find that FDM models with m(22) < 5x10(-22) are ruled out at 3 sigma confidence level. We expect that future LF measurements by James Webb Space Telescope, which will extend down to M-UV similar to -13 for z less than or similar to 10, with a survey volume that is comparable to the Hubble Ultra Deep Field would have the capability to constrain FDM models to m greater than or similar to 10(-21) eV.