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تسجيل مستخدم جديدReionization in Technicolor
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We present the Technicolor Dawn simulations, a suite of cosmological radiation-hydrodynamic simulations of the first 1.2 billion years. By modeling a spatially-inhomogeneous UVB on-the-fly with 24 frequencies and resolving dark matter halos down to $10^8 M_odot$ 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 $f_{mathrm{esc,gal}}(z)$ of ionizing photons that escape the interstellar medium, is adjusted to match observations of the Lyman-$alpha$ forest and the cosmic microwave background. With this single calibration, our simulations reproduce the history of reionization; the stellar mass-star formation rate relation of galaxies; the number density and metallicity of damped Lyman-$alpha$ absorbers (DLAs) at $zsim5$; the abundance of weak metal absorbers; the ultraviolet background (UVB) amplitude; and the Lyman-$alpha$ flux power spectrum at $z=5.4$. The galaxy stellar mass and UV luminosity functions are underproduced by $leq2times$, suggesting an overly vigorous feedback model. The mean transmission in the Lyman-$alpha$ forest is underproduced at $z<6$, indicating tension between measurements of the UVB amplitude and Lyman-$alpha$ transmission. The observed SiIV column density distribution is reasonably well-reproduced ($sim 1sigma$ 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.
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Traditional large-scale models of reionization usually employ simple deterministic relations between halo mass and luminosity to predict how reionization proceeds. We here examine the impact on modelling reionization of using more detailed models for
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We examine the reionization history of present-day galaxies by explicitly tracing the building blocks of halos from the Cosmic Reionization On Computers project. We track dark matter particles that belong to $z=0$ halos to trace the neutral fractions
at corresponding positions during rapid global reionization. The resulting particle reionization histories allow us to explore different definitions of a halos reionization redshift and to account for the neutral content of the interstellar medium. Consistent with previous work, we find a systematic trend of reionization redshift with mass - present day halos with higher masses have earlier reionization times. Finally, we quantify the spread of reionization times within each halo, which also has a mass dependence.
The reionization of the Universe ends the dark ages that started after the recombination era. In the case of H, reionization finishes around $zsim 6$. Faint star-forming galaxies are the best candidate sources of the H-ionizing radiation, although ac
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Motivated by recent measurements of the number density of faint AGN at high redshift, we investigate the contribution of quasars to reionization by tracking the growth of central supermassive black holes in an update of the Meraxes semi-analytic mode
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Increasing evidence suggests that cosmological sheets, filaments, and voids may be substantially magnetized today. The origin of magnetic fields in the intergalactic medium (IGM) is, however, currently uncertain. It seems well known that non-standard
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