Dynamic black holes through gravitational collapse

Analysis of the multipole moment of the curvatures on the horizon

Motoyuki Saijo

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

We have investigated several properties of rapidly rotating dynamic black holes generated by the gravitational collapse of rotating relativistic stars. At present, numerical simulations of the binary black hole merger are able to produce a Kerr black hole of Jfinal/Mfinal2 up to =0.91, of gravitational collapse from uniformly rotating stars up to Jfinal/ Mfinal2≈0.75, where Jfinal is the total angular momentum and Mfinal the total gravitational mass of the hole. We have succeeded in producing a dynamic black hole of spin Jfinal/Mfinal2≈0.95 through the collapse of differentially rotating relativistic stars. We have investigated those dynamic properties through diagnosing multipole moment of the horizon, and found the following two features. First, two different definitions of the angular momentum of the hole, the approximated Killing vector approach and dipole moment of the current multipole approach, make no significant difference to our computational results. Second, dynamic hole approaches a Kerr by gravitational radiation within the order of a rotational period of an equilibrium star, although the dynamic hole at the very forming stage deviates quite far from a Kerr. We have also discussed a new phase of quasi-periodic waves in the gravitational waveform after the ringdown in terms of the multipole moment of the dynamic hole.

Original languageEnglish
Article number124031
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Volume83
Issue number12
DOIs
Publication statusPublished - 2011 Jun 20
Externally publishedYes

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gravitational collapse
multipoles
horizon
curvature
moments
stars
angular momentum
gravitational waves
dynamic characteristics
waveforms
dipole moments
simulation

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

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abstract = "We have investigated several properties of rapidly rotating dynamic black holes generated by the gravitational collapse of rotating relativistic stars. At present, numerical simulations of the binary black hole merger are able to produce a Kerr black hole of Jfinal/Mfinal2 up to =0.91, of gravitational collapse from uniformly rotating stars up to Jfinal/ Mfinal2≈0.75, where Jfinal is the total angular momentum and Mfinal the total gravitational mass of the hole. We have succeeded in producing a dynamic black hole of spin Jfinal/Mfinal2≈0.95 through the collapse of differentially rotating relativistic stars. We have investigated those dynamic properties through diagnosing multipole moment of the horizon, and found the following two features. First, two different definitions of the angular momentum of the hole, the approximated Killing vector approach and dipole moment of the current multipole approach, make no significant difference to our computational results. Second, dynamic hole approaches a Kerr by gravitational radiation within the order of a rotational period of an equilibrium star, although the dynamic hole at the very forming stage deviates quite far from a Kerr. We have also discussed a new phase of quasi-periodic waves in the gravitational waveform after the ringdown in terms of the multipole moment of the dynamic hole.",
author = "Motoyuki Saijo",
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