Radiative feedback and cosmic molecular gas: the role of different radiative sources

TL;DR

This study uses multifrequency radiative hydrodynamical simulations to explore how different stellar populations and their spectra influence primordial star formation, gas heating, and feedback effects in the early universe.

Contribution

It introduces a comprehensive simulation framework coupling stellar spectra, hydrodynamics, and chemistry to analyze radiative feedback from various stellar populations.

Findings

Massive Population III stars can significantly ionize hydrogen and helium.

Radiative effects on star formation rates vary with stellar spectral energy distributions.

Soft SEDs have minor impacts on gas heating and photoevaporation.

Abstract

We present results from multifrequency radiative hydrodynamical chemistry simulations addressing primordial star formation and related stellar feedback from various populations of stars, stellar energy distributions (SEDs) and initial mass functions. Spectra for massive stars, intermediate-mass stars and regular solar-like stars are adopted over a grid of 150 frequency bins and consistently coupled with hydrodynamics, heavy-element pollution and non-equilibrium species calculations. Powerful massive population III stars are found to be able to largely ionize H and, subsequently, He and He$^+$, causing an inversion of the equation of state and a boost of the Jeans masses in the early intergalactic medium. Radiative effects on star formation rates are between a factor of a few and 1 dex, depending on the SED. Radiative processes are responsible for gas heating and photoevaporation, although emission from soft SEDs has minor impacts. These findings have implications for cosmic gas preheating, primordial direct-collapse black holes, the build-up of "cosmic fossils" such as low-mass dwarf galaxies, the role of AGNi during reionization, the early formation of extended disks and angular-momentum catastrophe.