The First Billion Years Simulation
While the first galaxies that formed in the Universe have yet to be observed directly, we are in a position to simulate in great detail the process of their formation.  Ahead of future missions which will observe early galaxies at redshifts z > 6, we are interested in making detailed predictions for the star formation history, chemical evolution, and emission properties of these galaxies.  To this end, we are planning an extraordinarily high resolution simulation with the state of the art N-Body/SPH simulation code GADGET-3 which will allow us to track the evolution of galaxies at very small scales while also allowing for a statistically significant sample of galaxies that can be compared to galaxies observed by missions such as ALMA, the JWST, and the E-ELT. Due to the heavy computational cost massive parallel computing facilities are involved in this project such as DEISA, the European network of parallel computers.
  1.  Transition from POPIII to POPII star formation
We are interested in understanding the transition from population III to population II star formation. Early accretion of gas with primordial metal abundance onto mini-halos of ~10^6 solar masses has been shown to lead to POPIII star formation. Within these mini-halos metal enrichment however, will take place quickly, and POPIII formation will be terminated. At this point it is not clear if continued accretion of cold primordial gas filaments will be able to rejuvenate POPIII formation or if the sites will change from the intersections of the cosmic filaments to the filaments themselves, which will have implications for the distribution of re-ionizing sources in the early universe and the mass assembly of galaxies.
The aim is combining high-resolution simulations of POPIII star formation with detailed metal enrichment to follow accurately radiative cooling and subsequent star formation in a metal enriched ISM.
  1.  Luminosity Function of Galaxies at z > 6
Recombination radiation, especially Ly-α emission, is commonly what is detected at redshifts z~5-6. The aim is to combine a radiative transfer routine, developed in the group, with the outputs of the SPH simulation to determine the temperature, density, and velocity profiles around galaxies. Furthermore, the goal is to compute the observed fluxes expected from a galaxy in optically thin emission lines (Hα, HeII 1640, etc.) and to calculate the radiative transfer of Ly-α.
  1.  Formation and growth of seed black holes from POPIII stars
Massive POPIII stars at the end of their life end up as black holes that can provide the seeds for super-massive black holes. Of particular interest will be if possible feedback from these black holes is able to influence subsequent star formation. Several key questions could be answered: what is the fate of these black holes? Do they merge? What is the relation between the black hole at the centre of the primordial galaxies and the host stellar mass? Are the local observed relations between host galaxy and black hole already in place at high redshift, and what is the contribution from high-z black holes to the re-ionizing background in the Universe?
  1.  The fate of the first galaxies
Once the first galaxies have finished their POPIII star formation phase, they will enter an episode of growth that is still dominated by large accretion rates by cold gaseous filaments and mergers. We are interested in following the path of these galaxies to intermediate redshifts (around z=2) to investigate their properties at later times. This will help establish if signatures of the early formation epoch are still present and detectable at later times.