

7 Summary
Relativistic binaries are tracers for the rich dynamical evolution
of globular clusters. The populations of these objects are the
result of an interplay between the gravitational dynamics of large
-body systems, the dynamics of mass transfer, the
details of stellar evolution, and the effect of the gravitational
field of the galaxy. The gravitational dynamics of globular
clusters can enhance the population of short period binaries of
main-sequence stars as well as inject compact objects such as white
dwarfs and neutron stars into stellar binary systems. Once they are
in such systems, the details of stellar evolution and mass transfer
in close binary systems govern the likely end products of the
dynamical interaction between the two stars. Furthermore, most
models of the evolution of the core of a globular cluster rely on
the gradual hardening and ejection of binary systems to delay the
onset of core collapse. The hardening of binaries in the core of
globular clusters will produce relativistic binaries, but it will
also eventually eject these systems as they gain larger and larger
recoil velocities in each subsequent encounter. The threshold for
ejection from a globular cluster depends both upon the
gravitational potential of the cluster itself and the gravitational
potential of its environment generated by the Milky Way. As the
globular cluster orbits the Milky Way, its local environment
changes. Consequently, if other dynamical processes (such as
gravothermal oscillations) do not dominate, the globular cluster’s
population of relativistic binaries may also reflect the past
orbital history of the globular cluster.
Over the last decade, observational techniques
and technology have improved to the extent that significant
discoveries are being made regularly. At this point, the bottleneck
in observations of binary millisecond pulsars, low-mass X-ray
binaries, and cataclysmic variables is time, not technology. As
these observational techniques are brought to bear on more
clusters, more discoveries are bound to be made. In the next
decade, the possibility of using gravitational wave astronomy to
detect relativistic binaries brings the exciting possibility of
identifying the populations of electromagnetically invisible
objects such as detached WD and NS binaries and black hole binaries
in globular clusters. These observations can only help to improve
the understanding of the complex and interesting evolution of these
objects and their host globular clusters.

