Following the cosmic evolution of pristine gas. III. the observational consequences of the unknown properties of population III stars

Richard Sarmento, Evan Scannapieco, Benoit Côté

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

We study the observational consequences of several unknown properties of Population III stars using large-scale cosmological simulations that include a subgrid model to track the unresolved mixing of pollutants. Varying the value of the critical metallicity that marks the boundary between Population III and Population II star formation across 2 dex has a negligible effect on the fraction of Population III stars formed and the subsequent fraction of Population III flux from high-redshift galaxies. However, adopting a lognormal initial mass function (IMF) for Population III stars, in place of a baseline Salpeter IMF, results in a Population III star formation rate density that is 1/4 of the baseline rate. The flux from high-redshift galaxies modeled with this IMF is highly bimodal, resulting in a tiny fraction of z ≤ 8 galaxies with more than 75% of their flux coming from Population III stars. However, at z = 9, right before reionization in our simulations, ≈20% of galaxies are Population III-bright with m UV ≤ 31.4 mag, and at least 75% of their flux is generated by Population III stars. Additionally, the lognormal Population III IMF results in a population of carbon-enhanced, metal-poor stars in reasonable agreement with MW halo observations. Our analysis supports the conclusion that the Population III IMF was dominated by stars in the 20-120 M range that generate supernovae with carbon-enhanced ejecta.

Original languageEnglish (US)
Article number206
JournalAstrophysical Journal
Volume871
Issue number2
DOIs
StatePublished - Feb 1 2019

Keywords

  • Population III
  • cosmology: Theory
  • early universe
  • evolution
  • galaxies: High-redshift
  • stars: Formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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