Gravitational wave extraction in simulations of rotating stellar core collapse

Journal Article · Tue Mar 15 00:00:00 EDT 2011 · Physical Review. D, Particles Fields

DOI:https://doi.org/10.1103/PHYSREVD.83.064008· OSTI ID:21537528

Reisswig, C ^[1]; Ott, C D ^[1]; Sperhake, U ^[2]; Schnetter, E ^[3]

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1. TAPIR, MC 350-17, California Institute of Technology, 1200 East California Boulevard, Pasadena, California 91125 (United States)
2. Institut de Ciencies de l'Espai (CSIC-IEEC), Facultat de Ciencies, Campus UAB, E-08193 Bellaterra (Spain)
3. Center for Computation and Technology, Louisiana State University, 216 Johnston Hall, Baton Rouge, Louisiana 70803 (United States)

We perform simulations of general relativistic rotating stellar core collapse and compute the gravitational waves (GWs) emitted in the core-bounce phase of three representative models via multiple techniques. The simplest technique, the quadrupole formula (QF), estimates the GW content in the spacetime from the mass-quadrupole tensor only. It is strictly valid only in the weak-field and slow-motion approximation. For the first time, we apply GW extraction methods in core collapse that are fully curvature based and valid for strongly radiating and highly relativistic sources. These techniques are not restricted to weak-field and slow-motion assumptions. We employ three extraction methods computing (i) the Newman-Penrose (NP) scalar {Psi}{sub 4}, (ii) Regge-Wheeler-Zerilli-Moncrief master functions, and (iii) Cauchy-characteristic extraction (CCE) allowing for the extraction of GWs at future null infinity, where the spacetime is asymptotically flat and the GW content is unambiguously defined. The latter technique is the only one not suffering from residual gauge and finite-radius effects. All curvature-based methods suffer from strong nonlinear drifts. We employ the fixed-frequency integration technique as a high-pass waveform filter. Using the CCE results as a benchmark, we find that finite-radius NP extraction yields results that agree nearly perfectly in phase, but differ in amplitude by {approx}1%-7% at core bounce, depending on the model. Regge-Wheeler-Zerilli-Moncrief waveforms, while, in general, agreeing in phase, contain spurious high-frequency noise of comparable amplitudes to those of the relatively weak GWs emitted in core collapse. We also find remarkably good agreement of the waveforms obtained from the QF with those obtained from CCE. The results from QF agree very well in phase and systematically underpredict peak amplitudes by {approx}5%-11%, which is comparable to the NP results and is certainly within the uncertainties associated with core collapse physics.

• OSTI ID: 21537528
• Journal Information: Physical Review. D, Particles Fields, Vol. 83, Issue 6; Other Information: DOI: 10.1103/PhysRevD.83.064008; (c) 2011 American Institute of Physics; ISSN 0556-2821
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
AMPLITUDES
APPROXIMATIONS
BENCHMARKS
EXTRACTION
GRAVITATIONAL COLLAPSE
GRAVITATIONAL WAVES
MASS
NOISE
NONLINEAR PROBLEMS
PEAKS
QUADRUPOLES
RELATIVISTIC RANGE
SIMULATION
SPACE-TIME
STARS
WAVE FORMS
CALCULATION METHODS
ENERGY RANGE
MULTIPOLES
SEPARATION PROCESSES