MareNostrum simulation
Dark matter and gas in a halo from the MareNostrum simulation.
The MareNostrum simulation is the largest cosmological N-body/hydrodynamic simulation performed to date. It uses adaptive mesh refinement to achieve a resolution of 1-2 kpc, about the size of a small galaxy. This is important because so-called ‘dwarf’ galaxies are by far the most commonly occuring in the Universe, especially at early times, and they may play an important role in the evolution of the intergalactic medium.
I am particularly interested in how galaxies affect (and are in turn affected by) their surroundings. The group of 4 colourful pictures to the left show the region of space around a large spiral galaxy - which is accompanied by several smaller ‘satellite’ galaxies - at a redshift of 4, about 1.5 billion years after the big bang. They show (clockwise from top-left) the density of the dark matter and the density, metallicity and temperature of the intergalactic and interstellar gas. The metals in the gas were formed in stars and then thrown out of the galaxies by exploding supernovae.
Using templates of stellar spectra and a model for the absorption of light by intervening dust and gas, we can calculate how the galaxies in the simulation might appear through a powerful telescope (after correcting for redshifting of the light by the expansion of the Universe). These distant galaxies show a wide range of morphologies: some exhibit the spiral shapes often seen in nearby galaxies while many have disturbed appearances that are probably the result of recent collisions with neighbouring galaxies; there are even some pairs and groups of galaxies caught in the act of merging. Note the dark lanes in many of the images, caused by dust in disks of the galaxies.
'True colour' images of selected galaxies from the MareNostrum simulation.
You can see many more of my galaxy pictures here. To read more about this ongoing work and see even more pictures, visit the website of Projet Horizon.