BN4 - End of white dwarfs and type Ia Supernova |
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Speaker |
Subramanian, Sathyawageeswar |
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Coauthors |
Subramanian, Sathyawageeswar; Mukhopadhyay, Banibrata |
| Talk Title |
Magnetised Differentially Rotating Super-Chandrasekhar White Dwarfs in GRMHD : Stable Non-spherical Configurations |
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Abstract |
We extend the exploration of significantly super-Chandrasekhar magnetised white dwarfs by numerically computing axisymmetric stationary equilibria of differentially rotating magnetised polytropic compact stars in general relativity (GR), within the ideal magnetohydrodynamic regime. We use a general relativistic magnetohydrodynamic (GRMHD) framework that describes rotating and magnetised 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 seconds. 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. |
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