Cosmological simulation

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Cosmological simulations are computer simulations that model and calculate the dynamic behavior of matter in large areas of space over periods of billions of years.

Simulations as an investigation method

For the investigation of structure formation in the universe, these simulations have so far provided decisive findings. They represent the temporal development of an arrangement of dark matter in a space. A popular representative is the millennium simulation . The simulations carried out so far differ mainly in the quality of their resolution and the size of the simulated volume.

Global simulations

At the beginning of the simulation, global simulations contain a large number of evenly distributed dark matter particles and generate filaments and voids in the course of the simulation . These are structures that correspond to the largest in the observable universe. The aforementioned Millennium Simulation is one of the global simulations. The purpose of such simulations is to compare the observed structure of the universe with the predictions and thus to check the parameters of the ΛCDM model (pronounced: Lambda-CDM). It is a success that the ΛCDM parameters lead to a bottom-up structure formation with great similarity to the observation situation. In addition, the early appearance of quasars a few 100 million years after the Big Bang, which was determined in the Sloan Digital Sky Survey , is compatible with the simulation result.

Local simulations

Local simulations such as the Aquarius simulation consider the development of a single dark matter halo . The Aquarius halos are similar in mass and cosmic neighborhood to the Milky Way halo. This similarity enables statistical predictions to be made about the expected density and speed distribution of dark matter within the Milky Way. Such predictions are interesting for the attempt of the direct detection of dark matter, because in principle they make verifiable statements in the laboratory about the energy and direction of movement of the particles in the area in which the sun and earth move around the galactic center. They also predict the pattern of gamma rays observed from Earth that annihilation could create dark matter. In this radiation, an observer should be able to observe a radiation intensity over the entire sky which corresponds to the amount of dark matter lying in the line of sight. This would be an overlay of two patterns. One would be triggered by the halo itself, with its roughly ellipsoidal shape and evenly decreasing density towards the outside. The greatest intensity could be observed in the direction of the galactic center, and from there it would decrease in all directions. The lowest intensity occurs near the antipodal point to the center. The second component of the pattern would be many small-scale increases in brightness in the order of magnitude and number of predicted subhalos . Should this radiation distribution be observed, not only would the energy of these dark matter particles be known, but also their large-scale distribution in our Milky Way.

Individual evidence

  1. ^ V. Springel, et al .: The Aquarius Project: the subhalos of galactic halos Mon. Not. Roy. Astron. Soc. 391: 1685-1711, 2008; arxiv : 0809.0898 .
  2. Press release of the Max Planck Society on Millennium Simulation
  3. M. Vogelsberger, et al .: Phase-space structure in the local dark matter distribution and its signature in direct detection experiments . In: Monthly Notices of the Royal Astronomical Society . 395, 2009, pp. 797-811. bibcode : 2009MNRAS.395..797V .
  4. Image of the gamma radiation pattern
  5. V. Springel, et al .: A blueprint for detecting supersymmetric dark matter in the Galactic halo . arxiv : 0809.0894 . Revision published in Nature: V. Springel, et al .: Prospects for detecting supersymmetric dark matter in the Galactic halo . In: Nature . 456, 2008, pp. 73-76.