Ionizing photon production of Population III stars: effects of rotation, convection, and initial mass function

ABSTRACT The first stars are thought to be one of the dominant sources hydrogen reionization in early Universe, with their high luminosities and surface temperatures expected drive ionizing photon production rates. In this work, we take our Geneva stellar evolution models zero-metallicity predict rates photons capable ionize H, He i, ii, based on a blackbody approximation. We present analytical fits range 1.7–500 $\, \mathrm{M}_{\odot }$. then explore impact initial mass, rotation, convective overshooting for individual stars. have found that increase increasing mass. For rotational velocities considered see changes up 25 per cent produced. This varies mass species reflects properties due rotation. also higher increases by approximately 20 change here. populations, how as function (IMF) slope, minimum maximum masses. fixed population order 20–30 through varying nature IMF. work presents predictions most date Population III stars, provides insight into key evolutionary parameters contribution reionization.