  With the advanced gravitational wave detectors coming on line in the next 5
years, we expect to make the first detections of gravitational waves from
astrophysical sources, and study the properties of the waves themselves as
tests of General Relativity. In addition, these gravitational waves will be
powerful tools for the study of their astrophysical sources and source
populations. They carry information that is quite complementary to what can be
learned from electromagnetic or neutrino observations, probing the central
gravitational engines that power the electromagnetic emissions. Preparations
are being made to enable near-simultaneous observations of both gravitational
wave and electromagnetic observations of transient sources, using low-latency
search pipelines and rapid sky localization. We will review the many
opportunities for multi-messenger astronomy and astrophysics with gravitational
waves enabled by the advanced detectors, and the preparations that are being
made to quickly and fully exploit them.

General Relativity and Quantum Cosmology;High Energy Astrophysical Phenomena