Born–Infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy

Pereira, Jonas P.; Coelho, Jaziel G.; Lima, Rafael C. R. de

doi:10.1140/epjc/s10052-018-5849-2

Cited by 12 publications

(13 citation statements)

References 49 publications

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“…Different possibilities of generation of continuous GWs have already been proposed (see e.g., Bonazzola & Gourgoulhon 1996;De Araujo et al 2016a,b;Mukhopadhyay et al 2017;De Araujo et al 2017;Gao et al 2017;Franzon & Schramm 2017;Pereira et al 2018;De Araujo et al 2019, and references therein). More recently, Kalita & Mukhopadhyay (2019) show that continuous GWs can be emitted from rotating magnetized WDs and will possibly be detected by the upcoming GW detectors such as LISA, DECIGO and BBO.…”

Section: Introductionmentioning

confidence: 99%

Gravitational waves from fast-spinning white dwarfs

Sousa

Coelho

2020

Monthly Notices of the Royal Astronomical Society

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Two mechanisms of gravitational waves (GWs) emission in fast-spinning white dwarfs (WDs) are investigated: accretion of matter and magnetic deformation. In both cases, the GW emission is generated by an asymmetry around the rotation axis of the star. However, in the first case, the asymmetry is due to the amount of accreted matter on the magnetic poles, while in the second case it is due to the intense magnetic field. We have estimated the GW amplitude and luminosity for three binary systems that have a fast-spinning magnetized WD, namely, AE Aquarii, AR Scorpii and RX J0648.0-4418. We find that, for the first mechanism, the systems AE Aquarii and RX J0648.0-4418 can be observed by the space detectors BBO and DECIGO if they have an amount of accreted mass of δm ≥ 10 −5 M . For the second mechanism, the three systems studied require that the WD have a magnetic field above ∼ 10 9 G to emit GWs that can be detected by BBO. We also verified that, in both mechanisms, the gravitational luminosity has an irrelevant contribution to the spindown luminosity of these three systems. Therefore, other mechanisms of energy emission are needed to explain the spindown of these objects.

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Section: Introductionmentioning

confidence: 99%

Gravitational waves from fast-spinning white dwarfs

Sousa

Coelho

2020

Monthly Notices of the Royal Astronomical Society

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“…It also arises from the worldvolume action of D-branes in string theory. Some aspects of pulsar magnetospheres in BI effective theory were discussed previously in [2,19]. Here, we consider the corrected dipole geometry in the theory.…”

Section: The Bi Theorymentioning

confidence: 99%

“…where the only parameter is of dimension of mass squared: b = M 2 . The lower bound of M is constrained to be 4 × 10 −4 GeV by PVLAS [20] and 100 GeV by ATLAS in LHC [21] (see also [19]). From the Lagrangian, we can obtain the expression of S:…”

Section: The Bi Theorymentioning

confidence: 99%

The force-free dipole magnetosphere in nonlinear electrodynamics

Yang²,

Wang³

2020

Res. Astron. Astrophys.

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Quantum electrodynamics (QED) effects may be included in physical processes of magnetar and pulsar magnetospheres with strong magnetic fields. Involving the quantum corrections, the Maxwell electrodynamics is modified to non-linear electrodynamics. In this work, we study the force-free magnetosphere in non-linear electrodynamics in a general framework. The pulsar equation describing a steady and axisymmetric magnetosphere is derived, which now admits solutions with corrections. We derive the first-order non-linear corrections to the near-zone dipole magnetosphere in some popular non-linear effective theories. The field lines of the corrected dipole tend to converge on the rotational axis so that the fields in the polar region are stronger compared to the pure dipole case.

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“…In this case, the QED corrections should be included in the force-free magnetospheres and the Maxwell electrodynamics should be replaced by the non-linear theory. This has been discussed in magnetar magnetospheres (e.g., [2,3,4]), whose surface magnetic fields sometimes can be above 10 15 G. However, this is not the case for black hole magnetospheres. The astronomical black holes do not have their own magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Black hole magnetospheres in the Born–Infeld theory

Wang

2020

Int. J. Mod. Phys. D

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We study the force-free electrodynamics on rotating black holes in the Born-Infeld (BI) effective theory. The stream equation describing a steady and axisymmetric magnetosphere is derived. From its near-horizon behavior, we obtain the modified Znajek regularity condition, with which we find that the horizon resistivity in the BI theory is generally not a constant. As expected, the outer boundary condition far away from the hole remains unchanged. In terms of the conditions at both boundaries, we derive the perturbative solution of split monopole in the slow rotation limit. It is interesting to realise that the correction to the solution relies not only on the parameter in the BI theory, but also on the radius (or the mass) of the hole. We also show that the quantum effects can undermine the energy extraction process of the magnetosphere in the non-linear theory and the extraction rate gets the maximum in the Maxwell theory.The force-free magnetosphere can be used to extract the rotational energy of a rotating black hole. As a kind of Penrose process, the energy is extracted through the rotation of the magnetosphere dragged by the black hole spacetime. This process has become a promising mechanism nowadays that can explain the formation of powerful jets observed in many high energy objects, like AGN, GRB and microquasars.It is known that the magnetic fields on neutron stars are very high, even exceeding the quantum electrodynamics (QED) critical value. In this case, the QED corrections should be included in the force-free magnetospheres and the Maxwell electrodynamics should be replaced by the non-linear theory. This has been discussed in magnetar magnetospheres (e.g., [2,3,4]), whose surface magnetic fields sometimes can be above 10 15 G.However, this is not the case for black hole magnetospheres. The astronomical black holes do not have their own magnetic fields. The magnetic fields on them come from accretion and are usually far weaker (e.g., 10 4 G for a black hole with mass M = 10 9 M ⊙ [5]) than the QED critical value. But, the study of the black hole magnetosphere in non-linear electrodynamics is useful for that of the QED corrected magnetosphere near a magnetar where gravity is important. The latter can be obtained in a weak field limit of the former despite a difference of the inner boundary condition.The study of black hole magnetospheres in non-linear electrodynamics is also of theoretical interest. The force-free magnetospheres on black holes are not well understood even in the Maxwell theory. We still do not know well the structure and geometry of the field lines in the force-free magnetosphere. The extension to the non-linear theory help find the analytical properties of black hole magnetospheres in a general sense.Moreover, non-linear electrodynamics include quantum corrections to the Maxwell theory. As is known, strong quantum effects also happen in black holes. Thermal particles are excited and radiated in the near-horizon regions of black holes. It is interesting to examine the force-free non-lin...

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Born–Infeld magnetars: larger than classical toroidal magnetic fields and implications for gravitational-wave astronomy

Cited by 12 publications

References 49 publications

Gravitational waves from fast-spinning white dwarfs

Gravitational waves from fast-spinning white dwarfs

The force-free dipole magnetosphere in nonlinear electrodynamics

Black hole magnetospheres in the Born–Infeld theory

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