TY - JOUR
T1 - Reionization in technicolor
AU - Finlator, Kristian
AU - Keating, Laura
AU - Oppenheimer, Benjamin D.
AU - Davé, Romeel
AU - Zackrisson, Erik
N1 - Funding Information:
Our simulations were run on NMSU’s JOKER and XSEDE’s COMET supercomputers; for advice and support we thank the NMSU ICT department and XSEDE. We thank Moire Prescott, Caitlin Doughty, Valentina D’Odorico, Zheng Cai, Lise Christensen, and Marc Rafel-ski for helpful comments and conversations. George Becker we thank particularly warmly for encouragement and helpful comments on the draft. KF thanks Claudia Scarlata for organizing the conference ‘Distant Galaxies from the Far South’, where the thinking for this work matured significantly. We also thank the anonymous referee for a sharp-eyed and supportive report that improved the paper. Our work made use of the WebPlotDigitizer tool (https://automeris.io/WebPlotDigitizer), for which we thank A. Ro-hatgi. This research would also have been quite impossible without the NASA Astrophysics Data System and the arXiv eprint service. EZ acknowledges funding from the Swedish National Space Board, and LK acknowledges support from a fellowship from the Canadian Institute for Theoretical Astrophysics. The Cosmic Dawn Center is funded by the Danish National Research Foundation.
Publisher Copyright:
© 2018 The Author(s).
PY - 2018/10
Y1 - 2018/10
N2 - We present the Technicolor Dawn simulations, a suite of cosmological radiation hydrodynamic simulations of the first 1.2 billion yr. By modelling a spatially inhomogeneous ultraviolet background (UVB) on the fly with 24 frequencies and resolving dark matter haloes down to 108 M⊙ within 12 h-1 Mpc volumes, our simulations unify observations of the intergalactic and circumgalactic media, galaxies, and reionization into a common framework. The only empirically tuned parameter, the fraction fesc, gal(z) of ionizing photons that escape the interstellar medium, is adjusted to match observations of the Lyman-α forest and the cosmic microwave background. With this single calibration, our simulations reproduce the history of reionization; the stellar mass and star formation rate relation of galaxies; the number density and metallicity of damped Lyman-α absorbers (DLAs) at z ~ 5; the abundance of weak metal absorbers; the ultraviolet background amplitude; and the Lyman-α flux power spectrum at z = 5.4. The galaxy stellar mass and ultraviolet luminosity functions are underproduced by ≤ 2 ×, suggesting an overly vigorous feedback model. The mean transmission in the Lyman-α forest is underproduced at z < 6, indicating tension between measurements of the UVB amplitude and Lyman-α transmission. The observed Si IV column density distribution is reasonably well reproduced (~1σ low). By contrast, CIV remains significantly underproduced despite being boosted by an intense > 4 Ryd UVB. Solving this problem by increasing metal yields would overproduce both weak absorbers and DLA metallicities. Instead, the observed strength of high-ionization emission from high-redshift galaxies and absorption from their environments suggest that the ionizing flux from conventional stellar population models is too soft.
AB - We present the Technicolor Dawn simulations, a suite of cosmological radiation hydrodynamic simulations of the first 1.2 billion yr. By modelling a spatially inhomogeneous ultraviolet background (UVB) on the fly with 24 frequencies and resolving dark matter haloes down to 108 M⊙ within 12 h-1 Mpc volumes, our simulations unify observations of the intergalactic and circumgalactic media, galaxies, and reionization into a common framework. The only empirically tuned parameter, the fraction fesc, gal(z) of ionizing photons that escape the interstellar medium, is adjusted to match observations of the Lyman-α forest and the cosmic microwave background. With this single calibration, our simulations reproduce the history of reionization; the stellar mass and star formation rate relation of galaxies; the number density and metallicity of damped Lyman-α absorbers (DLAs) at z ~ 5; the abundance of weak metal absorbers; the ultraviolet background amplitude; and the Lyman-α flux power spectrum at z = 5.4. The galaxy stellar mass and ultraviolet luminosity functions are underproduced by ≤ 2 ×, suggesting an overly vigorous feedback model. The mean transmission in the Lyman-α forest is underproduced at z < 6, indicating tension between measurements of the UVB amplitude and Lyman-α transmission. The observed Si IV column density distribution is reasonably well reproduced (~1σ low). By contrast, CIV remains significantly underproduced despite being boosted by an intense > 4 Ryd UVB. Solving this problem by increasing metal yields would overproduce both weak absorbers and DLA metallicities. Instead, the observed strength of high-ionization emission from high-redshift galaxies and absorption from their environments suggest that the ionizing flux from conventional stellar population models is too soft.
KW - Dark ages
KW - First stars
KW - Galaxies: evolution
KW - Galaxies: formation
KW - Galaxies: high-redshift
KW - Intergalactic medium
KW - Quasars: absorption lines
KW - Reionization
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U2 - 10.1093/MNRAS/STY1949
DO - 10.1093/MNRAS/STY1949
M3 - Article
AN - SCOPUS:85055186050
VL - 480
SP - 2628
EP - 2649
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 2
ER -