Multipole moments of axisymmetric electrovacuum spacetimes

We construct sequences of rapidly rotating neutron stars in dilatonic Einstein-Gauss-Bonnet theory, employing two equations of state for the nuclear matter. We analyze the dependence of the physical properties of these neutron stars on the Gauss-Bonnet coupling strength. For a given equation of state we determine the physically relevant domain of rapidly rotating neutron stars, which is delimited by the set of neutron stars rotating at the Kepler limit, the set of neutron stars along the secular instability line, and the set of static neutron stars. As compared to Einstein gravity, the presence of the Gauss-Bonnet term decreases this domain, leading to lower values for the maximum mass as well as to smaller central densities. The quadrupole moment is decreased by the GaussBonnet term for rapidly rotating neutron stars, while it is increased for slowly rotating neutron stars. The universal relation between the quadrupole moment and the moment of inertia found in General Relativity appears to extend to dilatonic Einstein-Gauss-Bonnet theory with very little dependence on the coupling strength of the Gauss-Bonnet term. The neutron stars carry a small dilaton charge.

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“…We employ the definitions of Geroch and Hansen [79,80], and follow closely the later references [81][82][83].…”

Section: Discussionmentioning

confidence: 99%

“…Let ξ be a time-like Killing vector field on the space-time manifold with metric g and λ the squared norm of ξ. We then define the metric h on a 3-dimensional space by the projection In [81] the complex multipole tensors are defined recursively as follows,…”

Section: Discussionmentioning

confidence: 99%

Rapidly rotating neutron stars in dilatonic Einstein-Gauss-Bonnet theory

et al. 2016

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“…To extract the quadrupole moment of the compact solutions, we follow Geroch and Hansen [25,26] (see also [27,28]) and obtain…”

Section: Einstein-gauss-bonnet-dilaton Theorymentioning

confidence: 99%

Quadrupole moments of rapidly rotating compact objects in dilatonic Einstein-Gauss-Bonnet theory

2014

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We consider rapidly rotating black holes and neutron stars in dilatonic Einstein-Gauss-Bonnet (EGBd) theory and determine their quadrupole moments, which receive a contribution from the dilaton. The quadrupole moment of EGBd black holes can be considerably larger than the Kerr value. For neutron stars, the universality property of theÎ-Q relation between the scaled moment of inertia and the scaled quadrupole moment appears to extend to EGBd theory.

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“…The first moments are calculated for (21) with the aid of the Hoenselaers-Perjés procedure [27] and have the form…”

Section: The Spacetime Around a Rotating Massive Charged Magnetic Dipolementioning

confidence: 99%

Frame dragging, vorticity and electromagnetic fields in axially symmetric stationary spacetimes

Herrera

González

Pachón

et al. 2006

Class. Quantum Grav.

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Abstract. We present a general study about the relation between the vorticity tensor and the Poynting vector of the electromagnetic field for axially symmetric stationary electrovacuum metrics. The obtained expressions allow to understand the role of the Poynting vector in the dragging of inertial frames. The particular case of the rotating massive charged magnetic dipole is analyzed in detail. In addition, the electric and magnetic parts of the Weyl tensor are calculated and the link between the later and the vorticity is established. Then we show that, in the vacuum case, the necessary and sufficient condition for the vanishing of the magnetic part is that the spacetime be static.

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Multipole moments of axisymmetric electrovacuum spacetimes

Cited by 86 publications

References 7 publications

Rapidly rotating neutron stars in dilatonic Einstein-Gauss-Bonnet theory

Rapidly rotating neutron stars in dilatonic Einstein-Gauss-Bonnet theory

Quadrupole moments of rapidly rotating compact objects in dilatonic Einstein-Gauss-Bonnet theory

Frame dragging, vorticity and electromagnetic fields in axially symmetric stationary spacetimes

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