The long and the short of it: modelling double neutron star and
  collapsar Galactic dynamics
  The work presented here examines populations of double compact binary systems
and tidally enhanced collapsars. We make use of BINPOP and BINKIN, two
components of a recently developed population synthesis package. Results focus
on correlations of both binary and spatial evolutionary population
characteristics. Pulsar and long duration gamma-ray burst observations are used
in concert with our models to draw the conclusions that: double neutron star
binaries can merge rapidly on timescales of a few million years (much less than
that found for the observed double neutron star population), common envelope
evolution within these models is a very important phase in double neutron star
formation, and observations of long gamma-ray burst projected distances are
more centrally concentrated than our simulated coalescing double neutron star
and collapsar Galactic populations. Better agreement is found with dwarf galaxy
models although the outcome is strongly linked to the assumed birth radial
distribution. The birth rate of the double neutron star population in our
models range from 4-160 Myr^-1 and the merger rate ranges from 3-150 Myr^-1.
The upper and lower limits of the rates results from including electron capture
supernova kicks to neutron stars and decreasing the common envelope efficiency
respectively. Our double black hole merger rates suggest that black holes
should receive an asymmetric kick at birth.
