  Sterile neutrinos comprise an entire class of dark matter models that,
depending on their production mechanism, can be hot, warm, or cold dark matter.
We simulate the Local Group and representative volumes of the Universe in a
variety of sterile neutrino models, all of which are consistent with the
possible existence of a radiative decay line at ~3.5 keV. We compare models of
production via resonances in the presence of a lepton asymmetry (suggested by
Shi & Fuller 1999) to "thermal" models. We find that properties in the highly
nonlinear regime - e.g., counts of satellites and internal properties of halos
and subhalos - are insensitive to the precise fall-off in power with
wavenumber, indicating that nonlinear evolution essentially washes away
differences in the initial (linear) matter power spectrum. In the quasi-linear
regime at higher redshifts, however, quantitative differences in the 3D matter
power spectra remain, raising the possibility that such models can be tested
with future observations of the Lyman-alpha forest. While many of the sterile
neutrino models largely eliminate multiple small-scale issues within the Cold
Dark Matter (CDM) paradigm, we show that these models may be ruled out in the
near future via discoveries of additional dwarf satellites in the Local Group.
