A toy model for global magnetar oscillation
A toy model for global magnetar oscillation
The presence of a magnetic field in a neutron star interior results in a dynamical coupling between the fluid core and the elastic crust. We consider a simple toy-model where this coupling is taken into account and compute the system’s mode oscillations. Our results suggest that the notion of pure torsional crust modes is not useful for the coupled system, instead all modes excite Alfvén waves in the core. However, we also show that among a rich spectrum of global MHD modes the ones most likely to be excited by a fractured crust are those for which the crust and the core oscillate in concert. For our simple model, the frequencies of these modes are similar to the “pure crustal” frequencies. We advocate the significant implications of these results for the attempted theoretical interpretation of QPOs during magnetar flares in terms of neutron star oscillations.
neutron stars, oscillations, magnetars
607-611
Glampedakis, Kostas
a08893ef-dd87-4ccb-9d65-3fd6c40fccca
Samuelsson, Lars
ce25b720-ee5b-4b1a-af84-c38a41399a62
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
1 April 2007
Glampedakis, Kostas
a08893ef-dd87-4ccb-9d65-3fd6c40fccca
Samuelsson, Lars
ce25b720-ee5b-4b1a-af84-c38a41399a62
Andersson, Nils
2dd6d1ee-cefd-478a-b1ac-e6feedafe304
Glampedakis, Kostas, Samuelsson, Lars and Andersson, Nils
(2007)
A toy model for global magnetar oscillation.
Astrophysics and Space Science, 308 (1-4), .
(doi:10.1007/s10509-007-9350-x).
Abstract
The presence of a magnetic field in a neutron star interior results in a dynamical coupling between the fluid core and the elastic crust. We consider a simple toy-model where this coupling is taken into account and compute the system’s mode oscillations. Our results suggest that the notion of pure torsional crust modes is not useful for the coupled system, instead all modes excite Alfvén waves in the core. However, we also show that among a rich spectrum of global MHD modes the ones most likely to be excited by a fractured crust are those for which the crust and the core oscillate in concert. For our simple model, the frequencies of these modes are similar to the “pure crustal” frequencies. We advocate the significant implications of these results for the attempted theoretical interpretation of QPOs during magnetar flares in terms of neutron star oscillations.
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e-pub ahead of print date: 22 March 2007
Published date: 1 April 2007
Keywords:
neutron stars, oscillations, magnetars
Identifiers
Local EPrints ID: 54969
URI: http://eprints.soton.ac.uk/id/eprint/54969
ISSN: 0004-640X
PURE UUID: 9e1c20f4-3767-455f-8465-11ea585ac196
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Date deposited: 01 Aug 2008
Last modified: 16 Mar 2024 03:02
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Contributors
Author:
Kostas Glampedakis
Author:
Lars Samuelsson
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