Fredagskollokvium: Gravitational waves and the two-body problem in general relativity

The gravitational wave detectors LIGO/VIRGO have discovered the
signals generated by the coalescence of binary black holes at
astronomical distances. The theoretical and numerical works on the
two-body problem in general relativity play a very important role when
deciphering and interpreting the gravitational wave signals. In this
talk, after a general review on gravitational waves and the problem 
of motion, we shall present the state-of-the-art on approximation methods 
in general relativity, such as the famous post-Newtonian expansion, 
which is an expansion when the orbital velocity of the black holes 
is small with respect to the speed of light. We shall show how useful 
is this approximation for the recent GW detections, and discuss the 
latest developments in this field.