Related papers: Reionization simulations powered by GPUs I: the st…
We introduce CRASH-AMR, a new version of the cosmological Radiative Transfer (RT) code CRASH, enabled to use refined grids. This new feature allows us to attain higher resolution in our RT simulations and thus to describe more accurately…
We study the process of cosmic reionization and estimate the ionizing background in the IGM using the Lyman series absorption in the spectra of the four quasars at 5.7<z<6.3 discovered by the SDSS. We derive the evolution of the ionizing…
A model of the density distribution in the intergalactic medium, motivated by that found in numerical simulations, is used to demonstrate the effect of a clumpy IGM and discrete sources on the reionization of the universe. In an…
Magnetic reconnection is an important process in astrophysical environments, as it re-configures magnetic field topology and converts magnetic energy into thermal and kinetic energy. In extreme astrophysical systems, such as black hole…
Intergalactic medium temperature is a powerful probe of the epoch of reionisation, as information is retained long after reionisation itself. However, mean temperatures are highly degenerate with the timing of reionisation, with the amount…
A serious concern for semi-analytical galaxy formation models, aiming to simulate multi-wavelength surveys and to thoroughly explore the model parameter space, is the extremely time consuming numerical solution of the radiative transfer of…
During reionization, neutral hydrogen in the intergalactic medium (IGM) imprints a damping wing absorption feature on the spectrum of high-redshift quasars. A detection of this signature provides compelling evidence for a significantly…
The contribution of stars in galaxies to cosmic reionisation depends on the star formation history in the Universe, the abundance of galaxies during reionisation, the escape fraction of ionising photons and the clumping factor of the…
We study the ionization and thermal evolution of the intergalactic medium during the epoch of \heii reionization by means of radiation hydrodynamical cosmological simulations. We post-process baryonic density fields from a standard…
Forming stars emit a substantial amount of radiation into their natal environment. We use ORION, an adaptive mesh refinement (AMR) three-dimensional gravito-radiation-hydrodynamics code, to simulate low-mass star formation in a turbulent…
Upcoming galaxy surveys and 21-cm experiments targeting high redshifts $z\gtrsim 6$ are highly complementary probes of galaxy formation and reionization. However, in order to expedite the large volume simulations relevant for 21-cm…
The reionization of the intergalactic medium at redshifts $z\gtrsim 6$ is expected to have a lasting impact on galaxies residing in low-mass dark matter halos. Unable to accrete or retain gas photo-heated to temperatures $T \gtrsim 10^4$ K,…
I use cosmological simulations that incorporate a physically motivated approximation to three-dimensional radiative transfer that recovers correct asymptotic ionization front propagation speeds for some cosmologically relevant density…
If the dark matter (DM) were composed of axions, then structure formation in the Universe would be suppressed below the axion Jeans scale. Using an analytic model for the halo mass function of a mixed DM model with axions and cold dark…
One of the key open questions in Cosmology is the nature of the sources that completed the cosmological hydrogen Reionization at z~5.2. High-z primeval galaxies have been long considered the main drivers for Reionization, with a minor role…
With the advent of the Square Kilometre Array Observatory (SKAO), scientists will be able to directly observe the Epoch of Reionization by mapping the distribution of neutral hydrogen at different redshifts. While physically motivated…
The epoch of hydrogen reionization is complete by $z=5$, but its progression at higher redshifts is uncertain. Measurements of Ly$\alpha$ forest opacity show large scatter at $z<6$, suggestive of spatial fluctuations in neutral fraction…
We describe a new methodology to analyze the reionization process in numerical simulations: The evo- lution of the reionization is investigated by focusing on the merger histories of individual HII regions. From the merger tree of ionized…
The reionization of the second electron of helium shapes the physical state of intergalactic gas at redshifts between 2 < z < 5. Because performing full in situ radiative transfer in hydrodynamic simulations is computationally expensive for…
We present numerical simulations of a 15 solar mass star in a suite of idealised environments in order to quantify the amount of energy transmitted to the interstellar medium (ISM). We include models of stellar winds, UV photoionisation and…