514 research outputs found
SGRs and AXPs as massive fast rotating highly magnetized white dwarfs: the case of SGR 0418+5729
We describe one of the so-called low magnetic field magnetars SGR 0418+5729,
as a massive fast rotating highly magnetized white dwarf following Malheiro et.
al. 2012. We give bounds for the mass, radius, moment of inertia, and magnetic
field for these sources, by requesting the stability of realistic general
relativistic uniformly rotating configurations. Based on these parameters, we
improve the theoretical prediction of the lower limit of the spin-down rate of
SGR 0418+5729. In addition, we compute the electron cyclotron frequencies
corresponding to the predicted surface magnetic fields.Comment: 6 pages, 1 figure, 1 table. The Thirteenth Marcel Grossmann Meeting:
On Recent Developments in Theoretical and Experimental General Relativity,
Astrophysics and Relativistic Field Theories - Proceedings of the MG13
Meeting on General Relativity (in 3 Volumes). Edited by Rosquist Kjell et. a
On the self-consistent general relativistic equilibrium equations of neutron stars
We address the existence of globally neutral neutron star configurations in
contrast with the traditional ones constructed by imposing local neutrality.
The equilibrium equations describing this system are the Einstein-Maxwell
equations which must be solved self-consistently with the general relativistic
Thomas-Fermi equation and -equilibrium condition. To illustrate the
application of this novel approach we adopt the Baym, Bethe, and Pethick (1971)
strong interaction model of the baryonic matter in the core and of the
white-dwarf-like material of the crust. We illustrate the crucial role played
by the boundary conditions satisfied by the leptonic component of the matter at
the interface between the core and the crust. For every central density an
entire new family of equilibrium configurations exists for selected values of
the Fermi energy of the electrons at the surface of the core. Each such
configuration fulfills global charge neutrality and is characterized by a
non-trivial electrodynamical structure. The electric field extends over a thin
shell of thickness between the core and the crust and
becomes largely overcritical in the limit of decreasing values of the crust
mass
The Klein first integrals in an equilibrium system with electromagnetic, weak, strong and gravitational interactions
The isothermal Tolman condition and the constancy of the Klein potentials
originally expressed for the sole gravitational interaction in a single fluid
are here generalized to the case of a three quantum fermion fluid duly taking
into account the strong, electromagnetic, weak and gravitational interactions.
The set of constitutive equations including the Einstein-Maxwell-Thomas-Fermi
equations as well as the ones corresponding to the strong interaction
description are here presented in the most general relativistic isothermal
case. This treatment represents an essential step to correctly formulate a
self-consistent relativistic field theoretical approach of neutron stars.Comment: To be published by Nuclear Physics
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