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Compact stars with strong magnetic fields (magnetars) have been observationally determined to have surface magnetic fields of order of 10^{14}-10^{15} G, the implied internal field strength being several orders larger. We study the equation…

High Energy Astrophysical Phenomena · Physics 2017-03-22 Monika Sinha , Banibrata Mukhopadhyay , Armen Sedrakian

Sharp phase transitions described by stiff equations of state allow for the existence of a third family of stable compact stars (besides white dwarfs and neutron stars), twin stars. In this work, we investigate for the first time the role…

Nuclear Theory · Physics 2019-03-06 R. O. Gomes , V. Dexheimer , S. Han , S. Schramm

We investigate the quantum hadrodynamic equation of state for neutron stars (with and without including hyperons) in the presence of strong magnetic fields. The deduced masses and radii are consistent with recent observations of high mass…

High Energy Astrophysical Phenomena · Physics 2012-11-19 Chung-Yeol Ryu , Myung-Ki Cheoun , Toshitaka Kajino , Tomoyuki Maruyama , Grant J. Mathews

The stability properties of newly born neutron stars, or proto--neutron stars, are considered. We take into account dissipative processes, such as neutrino transport and viscosity, in the presence of a magnetic field. In order to find the…

Astrophysics · Physics 2009-11-07 Juan A. Miralles , Jose A. Pons , V. Urpin

Dynamical instabilities in protoneutron stars may produce gravitational waves whose observation could shed light on the physics of core-collapse supernovae. When born with sufficient differential rotation, these stars are susceptible to a…

Current models of magnetars require extremely strong magnetic fields to explain their observed quiescent and bursting emission, implying that the field strength within the star's outer crust is orders of magnitude larger than the dipole…

Solar and Stellar Astrophysics · Physics 2016-04-07 Konstantinos N. Gourgouliatos , Toby Wood , Rainer Hollerbach

We study the problem of neutron star composition in the presence of a strong magnetic field. The effects of the anomalous magnetic moments of both nucleons and electrons are investigated in relativistic mean field calculations for a…

Astrophysics · Physics 2009-11-07 G. Mao , V. N. Kondratyev , A. Iwamoto , Z. Li , X. Wu , W. Greiner , I. N. Mikhailov

We solve the Einstein-Maxwell-Klein-Gordon system of equations and derive a compact, static axially symmetric magnetized object which is electrically neutral and made of two complex massive charged scalar fields. We describe several…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Víctor Jaramillo , Darío Núñez

Einstein-Cartan gravity is a close historical sibling of general relativity that allows for spacetime torsion. As a result, angular momentum couples to spacetime geometry in a similar way to energy. While consequences of this are well…

General Relativity and Quantum Cosmology · Physics 2024-12-17 Cédric Jockel , Leon Menger

It is shown that Einstein gravity tends to modify the electric and magnetic fields appreciably at distances of the order of the Compton wavelength. At that distance the gravitational field becomes spin dominated rather than mass dominated.…

General Relativity and Quantum Cosmology · Physics 2014-11-17 Kjell Rosquist

A four-parameter class of exact asymptotically flat solutions of the Einstein-Maxwell equations involving only rational functions is presented. It is able to describe the exterior field of a slowly or rapidly rotating neutron star with…

General Relativity and Quantum Cosmology · Physics 2009-12-30 Vladimir S. Manko , Eckehard W. Mielke , José D. Sanabria-Gómez

We construct parameter sets of the relativistic mean-field model fitted to the recent constraints on the asymmetry energy $J$ and the slope parameter $L$ for pure neutron matter. We find cases of unphysical behaviour, i.e.\ the appearance…

High Energy Astrophysical Phenomena · Physics 2018-12-19 Nadine Hornick , Laura Tolos , Andreas Zacchi , Jan-Erik Christian , Jürgen Schaffner-Bielich

We study the structure of spherically symmetric and static objects in the presence of a nonminimally coupled scalar field having a potential of the form $V(\phi)=-\mu^2\phi^2/2+\lambda\phi^4/4$. We numerically solve equations of the system…

General Relativity and Quantum Cosmology · Physics 2020-02-14 A. Savaş Arapoğlu , A. Emrah Yükselci

The general relativistic formulation of the problem of magnetically confined mountains on neutron stars is presented, and the resulting equations are solved numerically, generalising previous Newtonian calculations. The hydromagnetic…

High Energy Astrophysical Phenomena · Physics 2023-09-19 Pedro H. B. Rossetto , Jörg Frauendiener , Ryan Brunet , Andrew Melatos

Understanding the properties of the internal magnetic field of neutron stars remains a theoretical challenge. Over the last years, twisted-torus geometries have been considered both in Newtonian and general-relativistic equilibrium models,…

Solar and Stellar Astrophysics · Physics 2013-09-20 Riccardo Ciolfi , Luciano Rezzolla

We investigate the effects of very strong magnetic fields upon the equation of state of dense bayonic matter in which hyperons are present. In the presence of a magnetic field, the equation of state above nuclear density is significantly…

Astrophysics · Physics 2009-11-07 A. E. Broderick , M. Prakash , J. M. Lattimer

There is an increasing theoretical and observational evidence that the external magnetic field of magnetars may contain a toroidal component, likely of the same order of the poloidal one. Such "twisted magnetospheres" are threaded by…

High Energy Astrophysical Phenomena · Physics 2009-11-13 L. Pavan , R. Turolla , S. Zane , L. Nobili

In this work we investigate the effects of a non-minimally coupled quartic order scalar model on static neutron stars, with the non-minimal coupling in the Jordan frame being of the form $f(\phi ) = 1 + \xi\phi^2$. Particularly we derive…

General Relativity and Quantum Cosmology · Physics 2022-04-13 S. D. Odintsov , V. K. Oikonomou

We initiate numerical studies of differentially rotating magnetised (proto) neutron stars by studying - through construction from first principles - the coupling between an assumed differential rotation and an impressed magnetic field. For…

Astrophysics · Physics 2007-05-23 A. V. Thampan

We study the magnetic braking and viscous damping of differential rotation in incompressible, uniform density stars in general relativity. Differentially rotating stars can support significantly more mass in equilibrium than nonrotating or…

Astrophysics · Physics 2016-08-30 Yuk Tung Liu , Stuart L. Shapiro