https://doi.org/10.1140/epjc/s10052-014-3097-7
Regular Article - Theoretical Physics
Gravitational wave recoils in non-axisymmetric Robinson–Trautman spacetimes
1
Centro Brasileiro de Pesquisas Fisicas, Rua Xavier Sigaud 150, Rio de Janeiro, RJ, 22290-180, Brazil
2
Instituto Federal do Espírito Santo, Vitória, 29040-780, Brazil
* e-mail: ivano@cbpf.br
Received:
19
March
2014
Accepted:
11
September
2014
Published online:
7
October
2014
We examine the gravitational wave recoil and the associated kick velocities in non-axisymmetric Robinson–Trautman (RT) spacetimes. Characteristic initial data used for the dynamics correspond to non-head-on collisions of two black holes. We make a parameter study of the kick distributions for an extended range of the incidence angle 
in the initial data. In the range examined 
the kick distribution 
as a function of the symmetric mass 
satisfies an empirically modified Fitchett law, with a parameter 
that accounts for the nonzero net gravitational wave momentum flux in the equal-mass case. The law fits accurately the numerical data with a normalized rms error 
. The maximum kick velocity is 
for 
. A recent modification of the Fitchett law motivated by the effective-one-body formalism (Nagar in Phys Rev D 88:121501R, 2013) is also examined and, with the needed introduction of to account for non-head-on collisions, fits accurately the RT data with a normalized rms error 
. We construct the surface 
in the parameter space of RT initial data, which gives an overall view of the behavior of as the parameters change. The angular patterns of the gravitational waves emitted are analyzed and include the two polarization modes present in the radiative field of a non-head-on collision.
© SIF and Springer-Verlag Berlin Heidelberg, 2014
