GRMHD formulation of highly super-Chandrasekhar rotating magnetized white dwarfs: stable configurations of non-spherical white dwarfs

Subramanian, Sathyawageeswar and Mukhopadhyay, Banibrata (2015) GRMHD formulation of highly super-Chandrasekhar rotating magnetized white dwarfs: stable configurations of non-spherical white dwarfs. In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 454 (1). pp. 752-765.

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Abstract

Here we extend the exploration of significantly super-Chandrasekhar magnetized white dwarfs by numerically computing axisymmetric stationary equilibria of differentially rotating magnetized polytropic compact stars in general relativity (GR), within the ideal magnetohydrodynamic regime. We use a general relativistic magnetohydrodynamic (GRMHD) framework that describes rotating and magnetized axisymmetric white dwarfs, choosing appropriate rotation laws and magnetic field profiles (toroidal and poloidal). The numerical procedure for finding solutions in this framework uses the 3 + 1 formalism of numerical relativity, implemented in the open source XNS code. We construct equilibrium sequences by varying different physical quantities in turn, and highlight the plausible existence of super-Chandrasekhar white dwarfs, with masses in the range of 2-3 solar mass, with central (deep interior) magnetic fields of the order of 10(14) G and differential rotation with surface time periods of about 1-10 s. We note that such white dwarfs are candidates for the progenitors of peculiar, overluminous Type Ia supernovae, to which observational evidence ascribes mass in the range 2.1-2.8 solar mass. We also present some interesting results related to the structure of such white dwarfs, especially the existence of polar hollows in special cases.

Item Type:	Journal Article
Publication:	MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
Publisher:	OXFORD UNIV PRESS
Additional Information:	Copy right for this article belongs to the OXFORD UNIV PRESS, GREAT CLARENDON ST, OXFORD OX2 6DP, ENGLAND
Keywords:	gravitation; magnetic fields; MHD; stars: massive; supernovae: general; white dwarfs
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	24 Nov 2015 06:00
Last Modified:	24 Nov 2015 06:00
URI:	http://eprints.iisc.ac.in/id/eprint/52799

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