Evolution of a Milky Way sized system in the CDM universe
with dark energy
Formation of an object similar in size and mass to
our Milky Way galaxy. The region shown here is about one megaparsec across.
Particles
show the distribution of dark matter with the brightness indicating
the local density on a logarithmic stretch. The bright clumps of particles
are the dense sites where galaxies are expected to form. Our
"camera" is tracking the progenitor of the Milky Way, so that it is
always near the center of the field of view. We are also zooming-in
onto the progenitor as time goes on. The formation of objects
proceeds hierarchically in the Cold Dark Matter models. Small-mass
objects form first at z>10, they quickly grow in size and violently
merge with each other, creating increasingly larger and larger
system. This galactic "cannibalism" persists even to the present day
epoch (z=0) - you see multiple small clumps being "accreted". Note that
many of the "cannibalized" systems do not loose their identity and
become satellites orbiting in the gravitational pull of larger
systems. At the present epoch (z=0), the movie shows a rotation of
the formed dark matter halo, to better show its three-dimensional structure.
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 Astrophysical Institut Potsdam
by
Anatoly Klypin
(New Mexico State University)
Visualizations
by Andrey Kravtsov.
(Kavli Institute for Cosmological
Physics, The University of Chicago)