A Quantification of the Effects Using Different Stellar-population Synthesis Models for Epoch of Reionization

Abstract

The luminosity and spectral energy distribution of high- z galaxies are sensitive to the stellar-population synthesis (SPS) models. In this paper, we study the effects of different SPS models on the measurements of high- z galaxies and the budget of ionizing photons during the epoch of reionization by employing each of them in the semianalytical galaxy formation model L-Galaxies 2020 . We find that the different SPS models lead to ≲0.5 dex differences on the amplitudes of UV luminosity functions, while two modes of the same SPS model with and without the inclusion of binary stars lead to similar UV luminosity functions at z ≥ 6. Instead, the binary stars produce ∼40% more ionizing photons than the single stars, while such differences are smaller than those caused by different SPS models; for example, the BPASS model produces ∼100% more ionizing photons than other models.

Keywords

• Reionization
• High-redshift galaxies
• Galaxy evolution