The SPHINX cosmological simulations of the first billion years: The impact of binary stars on reionization

Joakim Rosdahl, Harley Katz, Jérémy Blaizot, Taysun Kimm, Léo Michel-Dansac, Thibault Garel, Martin Haehnelt, Pierre Ocvirk, Romain Teyssier

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

We present the SPHINX suite of cosmological adaptive mesh refinement simulations, the first radiation-hydrodynamical simulations to simultaneously capture large-scale reionization and the escape of ionizing radiation from thousands of resolved galaxies. Our 5 and 10 co-moving Mpc volumes resolve haloes down to the atomic cooling limit and model the interstellar medium with better than ≈ 10 pc resolution. The project has numerous goals in improving our understanding of reionization and making predictions for future observations. In this first paper, we study how the inclusion of binary stars in computing stellar luminosities impacts reionization, compared to a model that includes only single stars. Owing to the suppression of galaxy growth via strong feedback, our galaxies are in good agreement with observational estimates of the galaxy luminosity function. We find that binaries have a significant impact on the timing of reionization: with binaries, our boxes are 99.9 percent ionized by volume at z ≈ 7, while without them our volumes fail to reionize by z = 6. These results are robust to changes in volume size, resolution, and feedback efficiency. The escape of ionizing radiation from individual galaxies varies strongly and frequently. On average, binaries lead to escape fractions of ≈ 7-10 percent, about three times higher than with single stars only. The higher escape fraction is a result of a shallower decline in ionizing luminosity with age, and is the primary reason for earlier reionization, although the higher integrated luminosity with binaries also plays a subdominant role.

Original languageEnglish
Pages (from-to)994-1016
Number of pages23
JournalMonthly Notices of the Royal Astronomical Society
Volume479
Issue number1
DOIs
Publication statusPublished - 2018 Sep 1

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SPHINX
binary stars
escape
galaxies
simulation
luminosity
ionizing radiation
stellar luminosity
stars
boxes
halos
cooling
time measurement
retarding
inclusions
prediction
radiation
estimates
predictions

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Rosdahl, Joakim ; Katz, Harley ; Blaizot, Jérémy ; Kimm, Taysun ; Michel-Dansac, Léo ; Garel, Thibault ; Haehnelt, Martin ; Ocvirk, Pierre ; Teyssier, Romain. / The SPHINX cosmological simulations of the first billion years : The impact of binary stars on reionization. In: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 479, No. 1. pp. 994-1016.
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Rosdahl, J, Katz, H, Blaizot, J, Kimm, T, Michel-Dansac, L, Garel, T, Haehnelt, M, Ocvirk, P & Teyssier, R 2018, 'The SPHINX cosmological simulations of the first billion years: The impact of binary stars on reionization', Monthly Notices of the Royal Astronomical Society, vol. 479, no. 1, pp. 994-1016. https://doi.org/10.1093/mnras/sty1655

The SPHINX cosmological simulations of the first billion years : The impact of binary stars on reionization. / Rosdahl, Joakim; Katz, Harley; Blaizot, Jérémy; Kimm, Taysun; Michel-Dansac, Léo; Garel, Thibault; Haehnelt, Martin; Ocvirk, Pierre; Teyssier, Romain.

In: Monthly Notices of the Royal Astronomical Society, Vol. 479, No. 1, 01.09.2018, p. 994-1016.

Research output: Contribution to journalArticle

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T2 - The impact of binary stars on reionization

AU - Rosdahl, Joakim

AU - Katz, Harley

AU - Blaizot, Jérémy

AU - Kimm, Taysun

AU - Michel-Dansac, Léo

AU - Garel, Thibault

AU - Haehnelt, Martin

AU - Ocvirk, Pierre

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