FOREVER22: the first bright galaxies with population III stars at redshifts z simeq 10-20 and comparisons with JWST data

FOREVER22: the first bright galaxies with population III stars at redshifts z simeq 10-20 and comparisons with JWST data by Hidenobu Yajima et al. on Thursday 24 November We study the formation of the first galaxies in overdense regions modelled by the FOREVER22 simulation project. Our simulations successfully reproduce the star formation rates and the $M_{\rm UV}-M_{\rm star}$ relations of candidate galaxies at $z \sim 10-14$ observed by James Webb Space Telescope (JWST). We suggest that the observed galaxies are hosted by dark-matter haloes with $M_{\rm h} \sim 10^{11}~\rm M_{\odot}$ and are in short-period starburst phases. On the other hand, even simulated massive galaxies in overdense regions cannot reproduce the intense star formation rates and the large stellar masses of observed candidates at $z \sim 17$. Also, we show that the contribution of population III stars to the UV flux decreases as the stellar mass increases and it is a few percent for galaxies with $M_{\rm star} \sim 10^{8}~\rm M_{\odot}$. Therefore, a part of the observed flux by JWST could be the light from population III stars. Our simulations suggest that the UV flux can be dominated by population III stars and the UV-slope shows $\beta \lesssim -3$ if future observations would reach galaxies with $M_{\rm stars} \sim 10^{5}~\rm M_{\odot}$ at $z \sim 20$ of which the mass fraction of population III stars can be greater than 10 percent. arXiv: http://arxiv.org/abs/http://arxiv.org/abs/2211.12970v1