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Magnetized SASI: its mechanism and possible connection to some QPOs in XRBs

Dhang, Prasun and Sharma, Prateek and Mukhopadhyay, Banibrata (2018) Magnetized SASI: its mechanism and possible connection to some QPOs in XRBs. In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 476 (3). pp. 3310-3327.

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Official URL: http://dx.doi.org/ 10.1093/mnras/sty488

Abstract

The presence of a surface at the inner boundary, such as in a neutron star or a white dwarf, allows the existence of a standing shock in steady spherical accretion. The standing shock can become unstable in 2D or 3D; this is called the standing accretion shock instability (SASI). Two mechanisms - advective-acoustic and purely acoustic - have been proposed to explain SASI. Using axisymmetric hydrodynamic and magnetohydrodynamic simulations, we find that the advective-acoustic mechanism better matches the observed oscillation time-scales in our simulations. The global shock oscillations present in the accretion flow can explain many observed high frequency (greater than or similar to 100 Hz) quasi-periodic oscillations (QPOs) in X-ray binaries. The presence of a moderately strong magnetic field adds more features to the shock oscillation pattern, giving rise to low frequency modulation in the computed light curve. This low frequency modulation can be responsible for similar to 100 Hz QPOs (known as hHz QPOs). We propose that the appearance of hHz QPO determines the separation of twin peak QPOs of higher frequencies.

Item Type: Journal Article
Additional Information: Copy right for this article belong to OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Depositing User: Id for Latest eprints
Date Deposited: 16 May 2018 15:57
Last Modified: 31 Jan 2019 10:33
URI: http://eprints.iisc.ac.in/id/eprint/59859

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