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High-redshift galaxy formed in the Cold Dark Matter cosmology

see also this web page

This animation shows a disk galaxy at redshift of 4, when the Universe was only a billion and a half years old. The particles represent stars with the color indicative of the stellar age: white represents stars of age less than 100 million years, blue represents stars with ages smaller than half a billion years, and purple shows stars of older ages. The galaxy is assembled hierarchically by accreting small pieces and, occasionally, merging with another massive system. At this early epoch the frequency of mergers is particularly high. For example, you can see two clumps of young stars within the disk with tidal tails of stars trailing them. These small galaxies were accreted by the galaxy recently and are in the process of being "digested" by the massive system. Another small galaxy visible some distance away from the disk is in the queue to be accreted in the near future. Despite its young age, the galaxy posseses all of the main morphological characteristics of modern galaxies: grand design spiral arms, a bar, and a spherical bulge of older stars in the center. Note that all of these features arise in the model self-consistently under action of gravitatoinal and pressure forces from the random gaussian initial conditions, which are thought to correspond to the quantum fuzz in the primordial universe.

Questions and comments: Andrey Kravtsov (andrey@oddjob.uchicago.edu)

You can use this material if you include the proper credit:
simulations and visualizations were performed at the National Center for Supercomputer Applications
by Andrey Kravtsov (Center for Cosmological Physics, The University of Chicago)