  We study the angular momentum profiles both for dark matter and for gas
within virialized halos, using a statistical sample of halos drawn from
cosmological hydrodynamics simulations. Three simulations have been analyzed,
one is the ``non-radiative'' simulation, and the other two have radiative
cooling. We find that the gas component on average has a larger spin and
contains a smaller fraction of mass with negative angular momentum than its
dark matter counterpart in the non-radiative model. As to the cooling models,
the gas component shares approximately the same spin parameter as its dark
matter counterpart, but the hot gas has a higher spin and is more aligned in
angular momentum than dark matter, while the opposite holds for the cold gas.
After the mass of negative angular momentum is excluded, the angular momentum
profile of the hot gas component approximately follows the universal function
originally proposed by Bullock et al. for dark matter, though the shape
parameter $\mu$ is much larger for hot gas and is comfortably in the range
required by observations of disk galaxies. Since disk formation is related to
the distribution of hot gas that will cool, our study may explain the fact that
the disk component of observed galaxies contains a smaller fraction of low
angular momentum material than dark matter in halos.
