Freeke van de Voort

*** OUT OF DATE ***

Introduction

Stars form inside galaxies, but the rate at which this happens depends strongly on the mass of the galaxy and the age of the Universe. Therefore, the Universe is filled with a large variety of galaxies. As astronomers, we are curious to know why. One necessary ingredient for star formation is the gas from which the stars form. The reservoir of gas to fuel galaxies can be found in the intergalactic medium and in the haloes of galaxies. I use large cosmological, hydrodynamical simulations from the OWLS project to study the gas around galaxies. I am also working with a high-resolution zoom simulation from CLUES.

Accretion onto galaxies and haloes

I am interested in the growth of galaxies and their gaseous haloes. To form stars a galaxy needs gas as fuel. This gas accretes from the intergalactic medium onto the halo and from the halo onto the galaxy. Hydrodynamical simulations are an excellent tool to study this dynamical process. Both the physical properties of this gas and feedback from supernovae and active galactic nulei have large effects on the accretion rates and therefore on the efficiency of galaxy growth and star formation.

Observational signatures of accretion

It would be great if we could observe the accreting gas and confirm what we believe we have learnt from simulations. Because gas outside of galaxies is so diffuse, this is not easily done. I am currently investigating what the observable properties are.

Lyman-alpha radiative transfer

What is also keeping me busy at the moment is writing a Monte Carlo code to transfer Lyman-alpha radiation. The hard part is that these photons scatter many many times. So far, all tests indicate that it works. It's parallelised, but it still takes a long time to run. My plan is to speed it up and expand its functionality. I will then need to do much more work to apply this transfer of Lyman-alpha radiation in a full cosmological simulation. When successful, it will allow us to study Lyman-alpha emission from a large sample of galaxies in the universe.