Magnetars: Properties, Origin and Evolution

Mereghetti, S.; Pons, José A.; Melatos, A.

doi:10.1007/s11214-015-0146-y

Cited by 222 publications

(201 citation statements)

References 206 publications

(232 reference statements)

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“…a toroidal component) in the magnetospheres of strongly magnetized neutron stars (NSs) is inferred from observations of quiescent magnetar spectra (Rea et al 2008;Mereghetti et al 2015;Kaspi & Beloborodov 2017), which show features that are attributed to resonant cyclotron scattering due to the presence of magnetospheric currents. Such a twist could possibly be maintained by helicity transfer from the stellar interior, implying that the magnetosphere of a non-rotating star is not current-free (but is still force-free).…”

Section: Introductionmentioning

confidence: 99%

Long-term evolution of the force-free twisted magnetosphere of a magnetar

Akgün

Cerdá–Durán

Miralles

et al. 2017

Monthly Notices of the Royal Astronomical Society

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We study the long-term quasi-steady evolution of the force-free magnetosphere of a magnetar coupled to its internal magnetic field. We find that magnetospheric currents can be maintained on long timescales of the order of thousands of years. Meanwhile, the energy, helicity and twist stored in the magnetosphere all gradually increase over the course of this evolution, until a critical point is reached, beyond which a force-free magnetosphere cannot be constructed. At this point, some large scale magnetospheric rearrangement, possibly resulting in an outburst or a flare, must occur, releasing a large fraction of the stored energy, helicity and twist. After that, the quasi-steady evolution should continue in a similar manner from the new initial conditions. The timescale for reaching this critical point depends on the overall magnetic field strength and on the relative fraction of the toroidal field. The energy stored in the force-free magnetosphere is found to be up to ∼ 30% larger than the corresponding vacuum energy. This implies that for a 10 14 G field at the pole, the energy budget available for fast magnetospheric events is of the order of a few 10 44 erg. The spindown rate is estimated to increase by up to ∼ 60%, since the dipole content in the magnetosphere is enhanced by the currents present there. A rough estimate of the braking index n reveals that it is systematically n < 3 for the most part of the evolution, consistent with actual measurements for pulsars and early estimates for several magnetars.

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Section: Introductionmentioning

confidence: 99%

Long-term evolution of the force-free twisted magnetosphere of a magnetar

Akgün

Cerdá–Durán

Miralles

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…7 ) and with spin-down ratesṖ ∼ (10 −13 −10 −10 ) s/s, larger than the ones of normal pulsarsṖ ∼ (10 −15 − 10 −14 )s/s (see Refs. 8,9 ). Their X-ray luminosities L X , are explained by the decay of their huge magnetic fields.…”

Section: Sgrs/axps As Fast Rotating Massive and Highly Magnetized Whmentioning

confidence: 99%

White Dwarf Pulsars and Very Massive Compact Ultra Magnetized White Dwarfs

Otoniel

Lobato

Malheiro

et al. 2017

Int. J. Mod. Phys. Conf. Ser.

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In this work, we discuss white dwarf pulsars found recently making also reference of the possibility of some SGRs/AXPs being part of this class of pulsars. We also study the properties of very massive compact ultra magnetized white dwarfs that could be the progenitors candidates of super luminous type Ia supernovae, and also a previous stage of these white dwarf pulsars before the magnetic field decay. The structure of this ultra magnetized white dwarfs is obtained by solving the Einstein-Maxwell equations with a poloidal magnetic field in a fully general relativistic approach. The stellar interior is composed of a regular crystal lattice made of carbon ions immersed in a degenerate relativistic electron gas. We find that magnetized white dwarfs violate the standard Chandrasekhar mass limit significantly. We obtain a maximum white dwarf mass of around 2.12 M with an equatorial radius R ∼ 1596 Km, a central magnetic field of Bc = 1.74 × 10 14 G and Bs = 3.6 × 10 13 G at the stellar surface.

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“…Very recently, Mereghetti et al [22] reviewed explicitly the magnetars' properties, origin and evolution. Some interesting behaviors such as a wide array of X-ray activity including short bursts, large outbursts, giant flares, quasiperiodic oscillations, enhanced spin-down, glitches and antiglitches are displayed in magnetars and discussed by Kaspi and Beloborodov [23].…”

Section: Introductionmentioning

confidence: 99%

Magnetar crust electron capture for $$^{55}$$ 55 Co and $$^{56}$$ 56

Liu

2018

Eur. Phys. J. C

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Based on the relativistic mean-field effective interaction principle and random phase approximation theory in superstrong magnetic fields (SMFs), we present an analysis of the influence of SMFs on the electron Fermi energy, nuclear blinding energy, single-particle level structure and electron capture for 55 Co, and 56 Ni by the shell-model Monte Carlo method in the magnetar's crust. The electron capture rates increase by two orders of magnitude due to an increase in the electron Fermi energy and a change in single-particle level structure by SMFs. Then the rates decrease by more than two orders of magnitude due to an increase in the nuclear binding energy and a reduction in the electron Fermi energy by SMFs.

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Magnetars: Properties, Origin and Evolution

Cited by 222 publications

References 206 publications

Long-term evolution of the force-free twisted magnetosphere of a magnetar

Long-term evolution of the force-free twisted magnetosphere of a magnetar

White Dwarf Pulsars and Very Massive Compact Ultra Magnetized White Dwarfs

Magnetar crust electron capture for $$^{55}$$ 55 Co and $$^{56}$$ 56

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