2 research outputs found
The Head-On Collision of Two Equal Mass Black Holes Peter Anninos
We study the head-on collision of two equal mass, nonrotating black holes.
Various initial configurations are investigated, including holes which are
initially surrounded by a common apparent horizon to holes that are separated
by about , where is the mass of a single black hole. We have extracted
both and gravitational waveforms resulting from the
collision. The normal modes of the final black hole dominate the spectrum in
all cases studied. The total energy radiated is computed using several
independent methods, and is typically less than . We also discuss an
analytic approach to estimate the total gravitational radiation emitted in the
collision by generalizing point particle dynamics to account for the finite
size and internal dynamics of the two black holes. The effects of the tidal
deformations of the horizons are analysed using the membrane paradigm of black
holes. We find excellent agreement between the numerical results and the
analytic estimates.Comment: 33 pages, NCSA 94-048, WUGRAV-94-
Notes on the integration of numerical relativity waveforms
A primary goal of numerical relativity is to provide estimates of the wave
strain, , from strong gravitational wave sources, to be used in detector
templates. The simulations, however, typically measure waves in terms of the
Weyl curvature component, . Assuming Bondi gauge, transforming to the
strain reduces to integration of twice in time. Integrations
performed in either the time or frequency domain, however, lead to secular
non-linear drifts in the resulting strain . These non-linear drifts are not
explained by the two unknown integration constants which can at most result in
linear drifts. We identify a number of fundamental difficulties which can arise
from integrating finite length, discretely sampled and noisy data streams.
These issues are an artifact of post-processing data. They are independent of
the characteristics of the original simulation, such as gauge or numerical
method used. We suggest, however, a simple procedure for integrating numerical
waveforms in the frequency domain, which is effective at strongly reducing
spurious secular non-linear drifts in the resulting strain.Comment: 23 pages, 10 figures, matches final published versio