Dynamical Effect of the Turbulence of IGM on the Baryon Fraction
  Distribution
  We investigate the dynamical effect of the turbulence in baryonic
intergalactic medium (IGM) on the baryon fraction distribution. In the fully
developed nonlinear regime, the IGM will evolve into the state of turbulence,
containing strong and curved shocks, vorticity and complex structures.
Turbulence would lead to the density and velocity fields of the IGM to be
different from those of underlying collisionless dark matter. Consequently, the
baryon fraction f_b will deviate from its cosmic mean . We study these
phenomena with simulation samples produced by the weighted essentially
non-oscillatory (WENO) hybrid cosmological hydrodynamic/N-body code, which is
effective of capturing shocks and complex structures. We find that the
distribution of baryon fraction is highly nonuniform on scales from hundreds
kpc to a few of Mpc, and f_b varies from as low as 1% to a few times of the
cosmic mean. We further show that the turbulence pressure in the IGM is weakly
scale-dependent and comparable to the gravitational energy density of halos
with mass around 10^11 h-1 M\odot . The baryon fraction in halos with mass
equal to or smaller than 10^11 h^-1 M\odot should be substantially lower than
f_b^cosmic. Numerical results show that f_b is decreasing from 0.8 f_b^cosmic
at halo mass scales around 10^12 h^-1 M\odot to 0.3f_b^cosmic at 10^11 h^-1
M\odot and shows further decrease when halo mass is less than 10^11 h^-1
M\odot. The strong mass dependence of f_b is similar to the observed results.
  Although the simulated f_b in halos are higher than the observed value by a
factor of 2, the turbulence of the
  IGM should be an important dynamical reason leading to the remarkable missing
of baryonic matter in halos with mass \leq 10^12 h^-1 M\odot.
