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

Abstract

Proto-galaxies 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 75000 haloes between redshifts 27 and 6 that were extracted from the First Billion Years project, high-resolution cosmological hydrodynamics 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 virial mass below 1e8 solar mass results in low column densities that can be penetrated by radiation from young stars (age < 5 Myr). In haloes with virial mass above 1e8 solar mass supernova feedback is important, but only 30% of the haloes in this mass range have an escape fraction higher than 1%. We find a large range of escape fractions in haloes with similar properties, caused by different distributions of the dense gas in the halo. This makes it very hard to predict the escape fraction on the basis of halo properties and results in a highly anisotropic escape fraction. The strong mass dependence, the large spread and the large anisotropy of the escape fraction may strongly affect the topology of reionization and is something current models of cosmic reionization should strive to take into account.

21 pages, 17 figures, accepted for publication in MNRAS

References in corpus (17)

• Five-Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Cosmological Interpretation
• The effect of photo-ionization on the cooling rates of enriched, astrophysical plasmas
• Chemical enrichment in cosmological, smoothed particle hydrodynamics simulations
• Efficient Simulations of Early Structure Formation and Reionization
• The Effects of Stellar Rotation. II. A Comprehensive Set of Starburst99 Models
• Chemical enrichment of galaxy clusters from hydrodynamical simulations
• Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars
• An extremely primitive halo star
• Radiative transfer simulations of cosmic reionization I: methodology and initial results
• Probing the Formation of the First Low-Mass Stars with Stellar Archaeology
• A Local Clue to the Reionization of the Universe
• Inside-out or Outside-in: The topology of reionization in the photon-starved regime suggested by Lyman-alpha forest data
• Uncovering the Chemical Signature of the First Stars in the Universe
• The Effect of Galactic Properties on the Escape Fraction of Ionizing Photons
• Multi-frequency, thermally coupled radiative transfer with TRAPHIC: Method and tests
• CRASH2: colored packets and other updates
• Modeling Lyman continuum emission from young galaxies

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