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The First Billion Years project: the escape fraction of ionizing photons in the epoch of reionization

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Original languageEnglish
Pages (from-to)2544-2563
JournalMonthly Notices of the Royal Astronomical Society
Publication statusPublished - 1 Aug 2015


Protogalaxies forming in low-mass dark matter haloes are thought to provide the majority of ionizing photons needed to reionize the Universe, due to their high escape fractions of ionizing photons. We study how the escape fraction in high-redshift galaxies relates to the physical properties of the halo in which the galaxies form, by computing escape fractions in more than 75 000 haloes between redshifts 27 and 6 that were extracted from the First Billion Years project, high-resolution cosmological hydrodynamical simulations of galaxy formation. We find that the main constraint on the escape fraction is the gas column density in a radius of 10 pc around the stellar populations, causing a strong mass dependence of the escape fraction. The lower potential well in haloes with M200 ≲ 108 M⊙ results in low column densities that can be penetrated by radiation from young stars (age

    Research areas

  • radiative transfer, methods: numerical, galaxies: dwarf, galaxies: formation, galaxies: high-redshift

ID: 21768756