  Compact binary mergers are sources of gravitational waves, and can be
accompanied by electromagnetic signals. We discuss the possible features in the
kilonova emissions which may help distinguish the black hole - neutron star
mergers from the binary neutron stars. In addition, the amount of ejected
material may depend on whether the system undergoes the creation of a transient
hyper-massive, differentially rotating neutron star. In this context, the
numerical simulations of post-merger systems and their outflows are important
for our understanding of the nature of short GRB progenitor systems. In this
article, we present a suite of GR MHD simulations performed by the CTP PAS
astrophysics group, to model the neutrino driven disk winds and their
contribution to the kilonova emissions. The contribution of the disk wind to
the jet collimation and variability is also briefly discussed.
