L. Baiotti

Publications (3)7.37 Total impact

• Source

  Available from: arxiv.org

  Article: Gravitational-wave emission from rotating gravitational collapse in three dimensions.

  L Baiotti, I Hawke, L Rezzolla, E Schnetter
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  ABSTRACT: We present the first three-dimensional (3D) calculations of the gravitational-wave emission in the collapse of uniformly rotating stars to black holes. The initial models are polytropes which are dynamically unstable and near the mass-shedding limit. The waveforms have been extracted using a gauge-invariant approach and reflect the properties of both the initial stellar models and of newly produced black holes, being in good qualitative agreement with those computed in previous 2D simulations. The wave amplitudes, however, are about 1 order of magnitude smaller, giving, for a source at 10 kpc, a signal-to-noise ratio S/N approximately 0.25 for LIGO-VIRGO and S/N less than or approximately equal 4 for LIGO II.
  Physical Review Letters 05/2005; 94(13):131101. · 7.37 Impact Factor
• Article: 3-D collapse of rotating stars to Kerr black holes

  L Baiotti, I Hawke, P J Montero, F L Löffler, L Rezzolla, N Stergioulas, J A Font, E Seidel
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  ABSTRACT: We study gravitational collapse of uniformly rotating neutron stars to Kerr black holes, using a new three-dimensional, fully general relativistic hydrodynamics code, which uses high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. We investigate the gravitational collapse by carefully studying not only the dynamics of the matter, but also that of the trapped surfaces, i.e. of both the apparent and event horizons formed during the collapse. The use of these surfaces, together with the dynamical horizon framework, allows for a precise measurement of the black-hole mass and spin. The ability to successfully perform these simulations for sufficiently long times relies on excising a region of the computational domain which includes the singularity and is within the apparent horizon. The dynamics of the collapsing matter is strongly influenced by the initial amount of angular momentum in the progenitor star and, for initial models with sufficiently high angular velocities, the collapse can lead to the formation of an unstable disc in differential rotation.
  Journal of Physics Conference Series 04/2005; 8(1):86.
• Source

  Available from: Nikolaos Stergioulas

  Article: Three-dimensional relativistic simulations of rotating neutron-star collapse to a Kerr black hole

  L. Baiotti, I Hawke, P. J. Montero, F. Loeffler, L. Rezzolla, N. Stergioulas, J. A. Font, E. Seidel
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  ABSTRACT: We present a new three-dimensional fully general-relativistic hydrodynamics code using high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. Besides presenting a thorough set of tests which the code passes with very high accuracy, we discuss its application to the study of the gravitational collapse of uniformly rotating neutron stars to Kerr black holes. The initial stellar models are modelled as relativistic polytropes which are either secularly or dynamically unstable and with angular velocities which range from slow rotation to the mass-shedding limit. We investigate the gravitational collapse by carefully studying not only the dynamics of the matter, but also that of the trapped surfaces, i.e. of both the apparent and event horizons formed during the collapse. The use of these surfaces, together with the dynamical horizon framework, allows for a precise measurement of the black-hole mass and spin. The ability to successfully perform these simulations for sufficiently long times relies on excising a region of the computational domain which includes the singularity and is within the apparent horizon. The dynamics of the collapsing matter is strongly influenced by the initial amount of angular momentum in the progenitor star and, for initial models with sufficiently high angular velocities, the collapse can lead to the formation of an unstable disc in differential rotation. All the simulations performed with uniformly rotating initial data and a polytropic or ideal-fluid equation of state show no evidence of shocks or of the presence of matter on stable orbits outside the black hole.
  03/2004;