A Cosmological Structure Formation Simulation
Paul Bode (MIT),
Renyue Cen
(Princeton), Jeremiah Ostriker, (Princeton), and
Guohong Xu (UCSC),
as part of
GC3.
The simulation volume is a cube with each side 32 megaparsecs in
length (1 parsec = 3.3 light-years).
The pictures below show the projected density of a
slab 8 megaparsec deep taken from the center of the cube; a large cluster
containing X-ray emitting gas forms in the center as gravity
causes dense regions to collapse.
The colors show increasing density in the order black
(least dense), blue, green, yellow, red, white (most dense).
The computation was done on 64 and 128 nodes of the IBM SP2
at the
Cornell Theory Center;
it uses 134 million grid points and 17 million particles.
The total running time was four and a half days.
Gravity is computed using the
Particle-Mesh
method; gas equations
are solved using the TVD (Total Variation Diminishing) method.
(For details on this method see Renyue Cen and Jeremiah Ostriker
astro-ph/9404012
and the references therein.) The parallel code is discussed in more
detail in a HTML-format paper which
will appear in Supercomputing '96.
GIFS
The initial dark matter density (redshift z=40);
perturbations from the mean density are small:
Dark matter density at z=0 (today); the white region is
over 250 times denser than the mean:
The initial gas density (redshift z=40):
The gas density at z=0:
Temperature of the gas at z=0; black regions are less than
100,000 degrees Kelvin, white regions are over 50 million degrees:
Also available: what the gas would appear like in the
X-ray
at z=0.
MPEGS:
Smaller run (256 mesh points on a side)
Dark matter density evolution 95 kb
Gas density evolution 58 kb
Evolution of the gas temperature 23 kb
Evolution of the X-ray emissivity 13 kb
Larger run (512 mesh points on a side)
Dark matter density evolution 4.0 Mb
Gas density evolution 2.3 Mb
Evolution of the gas temperature 80 kb
Evolution of the X-ray emissivity 60 kb
(Note: not much happens early on in the temperature and X-ray
movies-- be patient.)