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)