The effects of binary stars on galaxies and metal-enriched gas during reionization
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The effects of binary stars on galaxies and metal-enriched gas during reionization. / Doughty, Caitlin; Finlator, Kristian.
In: Monthly Notices of the Royal Astronomical Society, Vol. 505, No. 2, 02.08.2021, p. 2207-2223.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - The effects of binary stars on galaxies and metal-enriched gas during reionization
AU - Doughty, Caitlin
AU - Finlator, Kristian
PY - 2021/8/2
Y1 - 2021/8/2
N2 - Binary stars are abundant in nearby galaxies, but are typically unaccounted for in simulations of the high-redshift Universe. Stellar population synthesis models that include the effects of binary evolution result in greater relative abundances of ionizing photons that could significantly affect the ambient ionizing background during the epoch of hydrogen reionization, additionally leading to differences in galaxy gas content and star formation. We use hydrodynamic cosmological simulations including in situ multifrequency radiative transfer to evaluate the effects of a high binary fraction in reionization-era galaxies on traits of the early intergalactic medium and the abundance of Hi and Heii ionizing photons. We further extend this to analyse the traits of enriched gas. In comparing metrics generated using a fiducial simulation assuming single stars with one incorporating a high binary fraction, we find that binary stars cause Hi reionization to complete earlier and at an accelerated pace, while also increasing the abundances of high-ionization metals (Civ and Siiv) in simulated absorption spectra while reducing the abundance of low-ionization states (Oi, Siii, and Cii). However, through increased photoheating of galactic and circumgalactic gas, they simultaneously reduce the rate of star formation in low-mass galaxies, slowing the ongoing process of enrichment and suppressing their own ionizing background. This potentially contributes to a slower Heii reionization process at , and further indicates that self-regulation of galaxies could be underestimated when neglecting binary stellar evolution.
AB - Binary stars are abundant in nearby galaxies, but are typically unaccounted for in simulations of the high-redshift Universe. Stellar population synthesis models that include the effects of binary evolution result in greater relative abundances of ionizing photons that could significantly affect the ambient ionizing background during the epoch of hydrogen reionization, additionally leading to differences in galaxy gas content and star formation. We use hydrodynamic cosmological simulations including in situ multifrequency radiative transfer to evaluate the effects of a high binary fraction in reionization-era galaxies on traits of the early intergalactic medium and the abundance of Hi and Heii ionizing photons. We further extend this to analyse the traits of enriched gas. In comparing metrics generated using a fiducial simulation assuming single stars with one incorporating a high binary fraction, we find that binary stars cause Hi reionization to complete earlier and at an accelerated pace, while also increasing the abundances of high-ionization metals (Civ and Siiv) in simulated absorption spectra while reducing the abundance of low-ionization states (Oi, Siii, and Cii). However, through increased photoheating of galactic and circumgalactic gas, they simultaneously reduce the rate of star formation in low-mass galaxies, slowing the ongoing process of enrichment and suppressing their own ionizing background. This potentially contributes to a slower Heii reionization process at , and further indicates that self-regulation of galaxies could be underestimated when neglecting binary stellar evolution.
KW - binaries: general
KW - galaxies: high-redshift
KW - intergalactic medium
KW - dark ages
KW - reionization
KW - first stars
KW - LYMAN CONTINUUM ESCAPE
KW - COSMOLOGICAL SIMULATIONS
KW - NEUTRAL HYDROGEN
KW - ALPHA FOREST
KW - CIRCUMGALACTIC MEDIUM
KW - INTERGALACTIC MEDIUM
KW - LUMINOSITY FUNCTION
KW - IONIZING PHOTONS
KW - REDSHIFT 6
KW - THAN 5
U2 - 10.1093/mnras/stab1448
DO - 10.1093/mnras/stab1448
M3 - Journal article
VL - 505
SP - 2207
EP - 2223
JO - Royal Astronomical Society. Monthly Notices
JF - Royal Astronomical Society. Monthly Notices
SN - 0035-8711
IS - 2
ER -
ID: 276162169