Coupling of radial and axial nonradial oscillations of compact stars: Gravitational waves from first-order differential rotation
- Institute of Cosmology and Gravitation, University of Portsmouth, Mercantile House, Portsmouth PO1 2EG (United Kingdom)
- Centro Studi e Ricerche E. Fermi, Compendio Viminale, 00184 Rome (Italy) and Dipartimento di Fisica 'G. Marconi', Universita di Roma 'La Sapienza'/Sezione INFN ROMA 1, P.le Aldo Moro 2, I-00185 Rome (Italy)
- Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy) and INFN sez. di Torino, Via P. Giuria 1, Turin (Italy)
- Institute for Gravitational Physics and Geometry, Center for Gravitational Wave Physics, and Department of Astronomy and Astrophysics, Penn State University, University Park, Pennsylvania 16802 (United States)
We investigate the nonlinear coupling between radial and nonradial oscillations of static spherically-symmetric neutron stars as a possible mechanism for the generation of gravitational waves that may lead to observable signatures. In this paper we concentrate on the axial sector of the nonradial perturbations. By using a multiparameter perturbative framework we introduce a complete description of the nonlinear coupling between radial and axial nonradial oscillations; we study the gauge-invariant character of the associated perturbative variables and develop a computational scheme to evolve the nonlinear coupling perturbations in the time domain. We present results of simulations corresponding to different physical situations and discuss the dynamical behavior of this nonlinear coupling. Of particular interest is the occurrence of signal amplifications in the form of resonance phenomena when a frequency associated with the radial pulsations is close to a frequency associated with one of the axial w-modes of the star. Finally, we mention possible extensions of this work and improvements towards more astrophysically motivated scenarios.
- OSTI ID:
- 20782909
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 73, Issue 8; Other Information: DOI: 10.1103/PhysRevD.73.084010; (c) 2006 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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