Second order gauge invariant measure of a tidally deformed black hole

作者：Ahmadi Nahid^*

来源：Journal of Cosmology and Astroparticle Physics, 2012, (8): 028.

DOI：10.1088/1475-7516/2012/08/028

• gravitational waves / theory
• astrophysical black holes
• GR black holes

In this paper, a Lagrangian perturbation theory for the second order treatment of small disturbances of the event horizon in Schwarzchild black holes is introduced. The issue of gauge invariance in the context of general relativistic theory is also discussed. The developments of this paper is a logical continuation of the calculations presented in [1], in which the first order coordinate dependance of the intrinsic and exterinsic geometry of the horizon is examined and the first order gauge invariance of the intrinsic geometry of the horizon is shown. In context of second order perturbation theory, It is shown that the rate of the expansion of the congruence of the horizon generators is invariant under a second order reparametrization; so it can be considered as a measure of tidal perturbation. A generally non-vanishing expression for this observable, which accomodates tidal perturbations and implies nonlinear response of the horizon, is also presented.

• 出版日期2012-8