Constraints on the Galaxy Formation Models during the Epoch of Reionization with High-redshift Observations

Abstract

We use high-resolution N-body dark matter simulations and L-Galaxies semianalytical galaxy formation models to explore the high-z galaxy properties and estimate the budget of ionizing photons. The parameters within L-Galaxies are obtained using a Markov Chain Monte Carlo (MCMC) method with high-z galaxy observations from JWST and other telescopes. We consider two versions of L-Galaxies, with and without dust correction on galaxy UV luminosities. With the best-fit parameters, both L-Galaxies 2015 and L-Galaxies 2020 reproduce well observations of UV luminosity functions, stellar mass functions, star formation rate densities, and ionizing photon emission efficiency. With the assumption of an escape fraction of 20%, all models produce more ionizing photons than the number of hydrogen atoms in the Universe at z > 6. The inclusion of dust correction within MCMC results in higher star formation efficiency, which predicts ∼50% more ionizing photons, with better consistency between the predicted stellar mass functions and observations.