THE EPOCH OF REIONIZATION
When first stars formed, their light started to heat up and ionize the Hydrogen contained in the surrounding medium. As structures evolved, new sources with harder spectra ignited and started to ionize also the Helium of the inter-galactic medium (IGM). This is the Epoch of Reionization (EoR), which shaped the properties of the baryonic content of the Universe. I make use of hydrodynamical and radiative-transfer numerical simulations in order to investigate in detail the processing taking place in the IGM before, during and after the EoR. The type of sources responsible for the reionization, their abundance and their spectra, the change in the statistical properties of the Universe, as well as the creation of the first magnetic fields are just some examples of the possible insight we can get using such instruments. Furthermore, present and future observations from new-generation instruments (e.g. PAPER, LOFAR, SKA, E-ELT) will finally allow to compare theoretical predictions with observations and to put tight constraints on the properties of our Universe during the Epoch of Reionization.
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Link to the papers: quasar-only reionization - Ly-alpha spikes - Magnetogenesis at cosmic dawn
Above: Different quantities from a slice through a simulation snapshot. Baryon overdensity (top left), temperature (bottom left), HII fraction (top right) and HeIII fraction (bottom right) in a slice.
Above: Pseudo-lightcone extracted from a simulation of cosmic reionization, color-coded with the hydrogen ionized fraction.
Left: Synthetic Lyman-alpha forest quasar sightline in the observer rest-frame, extracted from a numerical simulation. The normalized transmitted flux is shown in the bottom panel, while the top four panels show the IGM properties around the line of sight, namely (from top to bottom) baryonic overdensity, temperature, HI fraction and metallicity.