  N-body simulations of Cold Dark Matter (CDM) have shown that, in this
hierarchical structure formation model, dark matter halo properties, such as
the density profile, the phase-space density profile, the distribution of axial
ratio, the distribution of spin parameter, and the distribution of internal
specific angular momentum follow `universal' laws or distributions. Here we
study the properties of the first generation of haloes in a Hot Dark Matter
(HDM) dominated universe, as an example of halo formation through monolithic
collapse. We find all these universalities to be present in this case also.
Halo density profiles are very well fit by the Navarro et al (1997) profile
over two orders of magnitude in mass. The concentration parameter depends on
mass as $c \propto M^{0.2}$,reversing the dependence found in a hierarchical
CDM universe. However, the concentration-formation time relation is similar in
the two cases: earlier forming haloes tend to be more concentrated than their
later forming counterparts. Halo formation histories are also characterized by
two phases in the HDM case: an early phase of rapid accretion followed by
slower growth. Furthermore, there is no significant difference between the HDM
and CDM cases concerning the statistics of other halo properties: the
phase-space density profile; the velocity anisotropy profile; the distribution
of shape parameters; the distribution of spin parameter, and the distribution
of internal specific angular momentum are all similar in the two cases. Only
substructure content differs dramatically. These results indicate that mergers
do not play a pivotal role in establishing the universalities, thus
contradicting models which explain them as consequences of mergers.
