Numerical simulations of oscillating soliton stars: Excited states in spherical symmetry and ground state evolutions in 3D
Abstract
Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars [J. Balakrishna, E. Seidel, and W.-M. Suen, Phys. Rev. D 58, 104004 (1998).]. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short time scale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries.
Additional Information
©2008 The American Physical Society. (Received 17 October 2007; published 16 January 2008) We make extensive use of the Cactus Computational Toolkit, and its infrastructure for solving Einstein's equations. The simulations have been performed on the NCSA Tungsten cluster under computer allocation TGMCA02N014. We use the bspline package from the GNU software library [33] for interpolation of initial data and the PETSc solver [34] for solving elliptic equations. We especially want to thank Francisco S. Guzman for advice and encouragement at the beginning of the project, without which this paper would not have been completed. We would also like to acknowledge Francisco for developing the 3D evolution routine for the scalar field. We thank Peter Diener for useful discussions and Ed Seidel and Wai-Mo Suen for allowing us to use their 1D scalar field evolution code. We are very grateful to Doina Costescu and Cornel Costescu for hospitality, support, and discussions during R.B.'s stays in Champaign-Urbana. We have received partial funding from NSF grants PHY-0652952 and AST-0606710, and the Sofja Kovalevskaja Program from the Alexander Von Humboldt Foundation.Files
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Additional details
- Eprint ID
- 9682
- Resolver ID
- CaltechAUTHORS:BALprd08
- Created
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2008-02-29Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field