Séminaires : Documents

Recent tests of gravity theories with pulsar timing
Paulo Freire (Max-Planck-Institut für Radioastronomie)

In this talk, I describe how the precise timing of pulsars in several binary systems and one triple system have in the last two years yielded far more stringent tests tests of fundamental properties of space-time and gravity. We concentrate on a few tests of the universality of free fall (UFF), which include tests of the fundamental nature of gravitational waves. In general relativity, the latter have a purely quadrupolar structure, but in alternative gravity theories they can have a large dipolar component. All experiments we have made confirm, within experimental precision, the purely quadrupolar structure of gravitational waves, and more broadly the UFF. These results can be seen as tests of specific gravity theories. In particular, the radiative test with the ``double pulsar'' system, J0737-3039, confirms the general relativistic quadrupole emission formula to a precision of 0.00013 (95 % C. L.), which is 25 times more precise than the previous best radiative test with the the original binary (Hulse-Taylor) pulsar. General relativity passes all the new pulsar tests, and several classes of alternative theories of gravity are either ruled out or severely constrained.