Coherent Gravitational Waveforms and Memory from Cosmic String Loops. (arXiv:2002.05177v1 [gr-qc])

<a href="http://arxiv.org/find/gr-qc/1/au:+Aurrekoetxea_J/0/1/0/all/0/1">Josu C. Aurrekoetxea</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Helfer_T/0/1/0/all/0/1">Thomas Helfer</a>, <a href="http://arxiv.org/find/gr-qc/1/au:+Lim_E/0/1/0/all/0/1">Eugene A. Lim</a>

We construct, for the first time, the time-domain gravitational wave strain

waveform from the collapse of a strongly gravitating Abelian Higgs cosmic

string loop in full general relativity. We show that the strain exhibits a

large memory effect during merger, ending with a burst and the characteristic

ringdown as a black hole is formed. Furthermore, we investigate the waveform

and energy emitted as a function of string width, loop radius and string

tension $Gmu$. We find that the mass normalized gravitational wave energy

displays a strong dependence on the inverse of the string tension

$E_{mathrm{GW}}/M_0propto 1/Gmu$, with $E_{mathrm{GW}}/M_0 sim {cal

O}(1)%$ at the percent level, for the regime where $Gmugtrsim10^{-3}$.

Conversely, we show that the efficiency is only weakly dependent on the initial

string width and initial loop radii. Using these results, we argue that

gravitational wave production is dominated by kinematical instead of

geometrical considerations.

We construct, for the first time, the time-domain gravitational wave strain

waveform from the collapse of a strongly gravitating Abelian Higgs cosmic

string loop in full general relativity. We show that the strain exhibits a

large memory effect during merger, ending with a burst and the characteristic

ringdown as a black hole is formed. Furthermore, we investigate the waveform

and energy emitted as a function of string width, loop radius and string

tension $Gmu$. We find that the mass normalized gravitational wave energy

displays a strong dependence on the inverse of the string tension

$E_{mathrm{GW}}/M_0propto 1/Gmu$, with $E_{mathrm{GW}}/M_0 sim {cal

O}(1)%$ at the percent level, for the regime where $Gmugtrsim10^{-3}$.

Conversely, we show that the efficiency is only weakly dependent on the initial

string width and initial loop radii. Using these results, we argue that

gravitational wave production is dominated by kinematical instead of

geometrical considerations.

http://arxiv.org/icons/sfx.gif