Reionization in Technicolor
Abstract
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, C IV 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.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2018
- DOI:
- 10.1093/mnras/sty1949
- arXiv:
- arXiv:1805.00099
- Bibcode:
- 2018MNRAS.480.2628F
- Keywords:
-
- galaxies: evolution;
- galaxies: formation;
- galaxies: high-redshift;
- intergalactic medium;
- quasars: absorption lines;
- dark ages;
- reionization;
- first stars;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 24 pages, 17 figures, accepted to MNRAS