Data repository.
================

The files contain particle data in spheres of radius 5Mpc/h
centered on the minimum of the halo potential for the most massive
clusters in an N-body+SPH simulation of the Ostriker & Steinhardt
concordance model.
The simulation volume was a (periodic) cube of side length 150Mpc/h 
with 2x192^3 particles.  The simulation was evolved to z=0 including
only adiabatic gas physics (and shocks).
The halos were found with a FoF algorithm and the halo center
defined as the minimum of the potential including only the particles
within the initial FoF group.

The format of the files ending in .tipsy is binary Tipsy format, written
on a Pentium PC running Linux.

Masses are simply Omega_{CDM} and Omega_{B} for the dark and gas particles
respectively.  Positions are in units of the box length, 150Mpc/h, with the
minimum of the potential at the origin.
Velocities are in units of the expansion velocity across the box,
which at z=0 is aHL=15,000km/s.  This has the nice property that
the redshift space position of a particle is just its real space
position plus the line-of-sight component of the velocity.
No offset has been applied to the velocities, i.e. the COM motion is not
constrained to be zero.
The gas particles have densities measured in units of the mean
mass density, smoothing lengths in units of the box length and
internal energies in units of (aHL)^2.
[To convert internal energies to temperatures in keV multiply by
 0.1044*(Gamma-1)*mu*(aHL/100)^2
 where Gamma=5/3 and mu=0.588 (mean molecular weight for Yp=24%)]
The smoothing length for the dark particles and the potentials,
metallicities etc are not filled in.

The naming convention is "tpmsph_?.????_??.tipsy".  The name, tpmsph,
refers to the code which produced the files.  The second number (?.????)
is the scale-factor of the output, the third number is the halo number.
Halos are ordered in decreasing order of number of particles in the FoF
group (so decreasing mass).

Martin White.