The Millennium Simulation Project
The Millennium Simulation is a computer N-body simulation used to investigate how the distribution of matter in the universe has evolved over time, in particular, how the observed population of galaxies was formed.
For more details:
Paper: Simulating the joint evolution of quasars, galaxies and their large-scale distribution
Abstract: The cold dark matter model has become the leading theoretical paradigm for the formation of structure in the Universe. Together with the theory of cosmic inflation, this model makes a clear prediction for the initial conditions for structure formation and predicts that structures grow hierarchically through gravitational instability. Testing this model requires that the precise measurements delivered by galaxy surveys can be compared to robust and equally precise theoretical calculations. Here we present a novel framework for the quantitative physical interpretation of such surveys. This combines the largest simulation of the growth of dark matter structure ever carried out with new techniques for following the formation and evolution of the visible components. We show that baryon-induced features in the initial conditions of the Universe are reflected in distorted form in the low-redshift galaxy distribution, an effect that can be used to constrain the nature of dark energy with next-generation surveys.
Simulation movie (part-1)
This movie shows the dark matter distribution in the universe at the present time, based on the Millennium Simulation, the largest N-body simulation carried out thus far (more than 10^10 particles). By zooming in on a massive cluster of galaxies, the movie highlights the morphology of the structure on different scales, and the large dynamic range of the simulation (10^5 per dimension in 3D). The zoom extends from scales of several Gpc down to resolved substructures as small as ~10 kpc.
Credit: Springel et al., Max-Planck-Institute for Astrophysics
Simulation movie (part-2)
This movie shows a journey through the simulated universe. On the way, we visit a rich cluster of galaxies and fly around it. During the two minutes of the movie, we travel a distance for which light would need more than 2.4 billion years.
Credit: Springel et al., Max-Planck-Institute for Astrophysics
The Eris Simulation
Eris is a computer simulation of the Milky Way galaxy's physics.
For more details:
Paper: Forming Realistic Late-Type Spirals in a LCDM Universe: The Eris Simulation
Abstract: Simulations of the formation of late-type spiral galaxies in a cold dark matter LCDM universe have traditionally failed to yield realistic candidates. Here we report a new cosmological N-body/SPH simulation of extreme dynamic range in which a close analog of a Milky Way disk galaxy arises naturally. Termed Eris, the simulation follows the assembly of a galaxy halo of mass Mvir=7.9x10^11 Msun with a total of N=18.6 million particles (gas + dark matter + stars) within the final virial radius, and a force resolution of 120 pc. It includes radiative cooling, heating from a cosmic UV field and supernova explosions, a star formation recipe based on a high gas density threshold (nSF=5 atoms cm^-3 rather than the canonical nSF=0.1 atoms cm^-3), and neglects AGN feedback. At the present epoch, the simulated galaxy has an extended rotationally-supported disk with a radial scale length Rd=2.5 kpc, a gently falling rotation curve with circular velocity at 2.2 disk scale lenghts of V2.2=214 km/s, a bulge-to-disk ratio B/D=0.35, and a baryonic mass fraction that is 30% below the cosmic value. The disk is thin, is forming stars in the region of the Sigma_SFR - Sigma_HI plane occupied by spiral galaxies, and falls on the photometric Tully-Fisher and the stellar mass-halo virial mass relations. Hot (T>3x10^5 K), X-ray luminous halo gas makes only 26% of the universal baryon fraction and follows a flattened density profile proportional to r^-1.13 out to r=100 kpc. Eris appears then to be the first cosmological hydrodynamic simulation in which the galaxy structural properties, the mass budget in the various components, and the scaling relations between mass and luminosity are all consistent with a host of observational constraints.
Simulation movie
Next Page > Click here to watch the simulation movie