Talk detail

Participant	Boshkayev, Kuantay
Institution	Department of Physics, University of Rome "Sapienza" - Aldo Moro square, 5 - Rome - Rome, Lazio - Italy

Session	SF1	Accepted		Order	Time
Talk	Oral abstract	Title	SGRs and AXPs as Massive Fast Rotating Highly Magnetized White Dwarfs: the case of 1E 2259+586, SGR 0418+5729, and J1822.3-1606.
Co-authors
Abstract	A new rigorous theory of rotating white dwarfs (WDs) within Hartle’s general relativistic formalism is presented. The microphysical description (equation of state) is based on the recent developed relativistic Feynman-Metropolis-Teller treatment of a compressed atom in a Wigner-Seitz cell. Limits on the rotation period and its first time derivative (spin-down rate) are obtained. This new theory is applied to the study of Soft Gamma Ray Repeaters (SGRs) and Anomalous X-ray Pulsars (AXPs), which, as we show, can be described as massive fast rotating highly magnetized WDs, in full analogy with pulsars powered by rotating neutron stars. We analyze within this model the AXP prototype 1E 2259+586 and the so-called “low magnetic field magnetars” Swift J1822.3-1606 and SGR 0418+5729. We give upper and lower bounds for the mass, radius, moment of inertia, and magnetic field of these sources.

Session	SO4	Accepted		Order	Time
Talk	Oral abstract	Title	ON GENERAL RELATIVISTIC UNIFORMLY ROTATING WHITE DWARFS
Co-authors
Abstract	The properties of uniformly rotating white dwarfs (RWDs) are analyzed within the framework of general relativity. Hartle's formalism is applied to construct self-consistently the internal and external solutions to the Einstein equations. The WD matter is described by the relativistic Feynman-Metropolis-Teller equation of state which generalizes the Salpeter's one by fully taking into account the finite size of the nuclei, the Coulomb interactions as well as electroweak equilibrium in a self-consistent relativistic fashion. The physical parameters of RWDs are calculated as a function of the central density and rotation angular velocity. We construct the region of stability of RWDs taking into account the mass-shedding limit, inverse $\beta$-decay instability, and the boundary established by the turning points of constant angular momentum sequences. We found the minimum rotation periods $\sim 0.3$, $0.5$, $0.7$ and $2.2$ seconds for $^{4}$He, $^{12}$C, $^{16}$O, and $^{56}$Fe WDs, respectively. Correspondingly to the same chemical compositions, the maximum masses are $\sim 1.500$, $1.474$, $1.467$, $1.202$ $M_\odot$.