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We examine the evolution of the Parker instability in galactic disks using 3D numerical simulations. We consider a local Cartesian box section of a galactic disk, where gas, magnetic fields and cosmic rays are all initially in a…

Astrophysics of Galaxies · Physics 2015-12-24 Luiz Felippe S. Rodrigues , Graeme R. Sarson , Anvar Shukurov , Paul J. Bushby , Andrew Fletcher

We find general relativistic solutions of equilibrium magnetic field configurations in magnetars, extending previous results of Colaiuda et al. (2008). Our method is based on the solution of the relativistic Grad-Shafranov equation, to…

Solar and Stellar Astrophysics · Physics 2010-11-02 R. Ciolfi , V. Ferrari , L. Gualtieri , J. A. Pons

We have succeeded in obtaining magnetized star models that have extremely strong magnetic fields in the interior of the star. In our formulation, arbitrary functions of the magnetic flux function appear in the expression for the current…

High Energy Astrophysical Phenomena · Physics 2013-04-03 Kotaro Fujisawa , Shin'ichirou Yoshida , Yoshiharu Eriguchi

Disk accretion onto a magnetized star occurs in a variety of astrophysical contexts, from young stars to X-ray pulsars. The magnetohydrodynamic interaction between the stellar field and the accreting matter can have a strong effect on the…

Astrophysics · Physics 2009-10-31 Dmitri A. Uzdensky , Arieh Konigl , Christof Litwin

The evolution of large-scale magnetic fields in disk galaxies is investigated numerically. The gasdynamical simulations in a disk perturbed by spiral or bar potential are incorporated into the kinematic calculations of induction equations…

Astrophysics · Physics 2007-05-23 K. Otmianowska-Mazur , M. Chiba

We study the stability of poloidal magnetic fields anchored in a thin accretion disc. The two-dimensional hydrodynamics in the disc plane is followed by a grid-based numerical simulation including the vertically integrated magnetic forces.…

Astrophysics · Physics 2015-06-24 R. Stehle , H. C. Spruit

We study the global bending modes of a thin annular disc subject to both an internally generated magnetic field and a magnetic field due to a dipole embedded in the central star with axis aligned with the disc rotation axis. When there is a…

Astrophysics · Physics 2007-05-23 Vasso Agapitou , John C. B. Papaloizou , Caroline Terquem

A recipe is presented to construct an analytic, self-consistent model of a non-barotropic neutron star with a poloidal-toroidal field of arbitrary multipole order, whose toroidal component is confined in a torus around the neutral curve…

High Energy Astrophysical Phenomena · Physics 2015-01-26 Alpha Mastrano , Arthur George Suvorov , Andrew Melatos

From our radio continuum and polarization observations of a sample of spiral galaxies with different morphological types, inclinations, and star formation rates (SFR) we found that galaxies with low SFR have higher thermal fractions/…

Astrophysics · Physics 2008-06-13 Marita Krause

A full understanding of high-mass star formation requires the study of one of the most elusive components of the energy balance in the interstellar medium: magnetic fields. We report ALMA 1.2 mm, high-resolution (700 au) dust polarization…

We determine constraints on the form of axisymmetric toroidal magnetic fields dictated by hydrostatic balance in a type II superconducting neutron star with a barotropic equation of state. Using Lagrangian perturbation theory, we find the…

Astrophysics · Physics 2009-11-16 Taner Akgun , Ira Wasserman

We carry out the self-similar solutions of viscous-resistive accretion flows around a magnetized compact object. We consider an axisymmetric, rotating, isotheral steady accretion flow which contains a poloidal magnetic field of the central…

Astrophysics · Physics 2012-06-19 J. Ghanbari , F. Salehi , S. Abbassi

Upper main sequence stars, white dwarfs and neutron stars are known to possess stable, large-scale magnetic fields. Numerical works have confirmed that stable MHD equilibria can exist in non-barotropic, stably stratified stars. On the other…

Solar and Stellar Astrophysics · Physics 2015-06-23 C. Armaza , A. Reisenegger , J. A. Valdivia

We present a large-scale view of the magnetic field in the central 2deg * 2deg region of our Galaxy. The polarization of point sources has been measured in the J, H, and Ks bands using the near-infrared polarimetric camera SIRPOL on the 1.4…

Observations of clusters of galaxies show ubiquitous presence of X-ray cavities, presumably blown by the AGN jets. We consider magnetic field structures of these cavities. Stability requires that they contain both toroidal and poloidal…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Konstantinos Nektarios Gourgouliatos , Jonathan Braithwaite , Maxim Lyutikov

We present numerical simulations of a self-sustaining magnetic field in a differentially rotating non-convective stellar interior. A weak initial field is wound up by the differential rotation; the resulting azimuthal field becomes unstable…

Astrophysics · Physics 2009-11-11 J. Braithwaite , H. C. Spruit

Recent hydrodynamical simulations have shown that differentially rotating neutron stars formed in core-collapse supernovae may develop global non-axisymmetric instabilities even when $T/|W|$ (the ratio of the rotational kinetic energy $T$…

Solar and Stellar Astrophysics · Physics 2011-06-20 Wen Fu , Dong Lai

Magnetic fields in the stellar interiors are key candidates to explain observed core rotation rates inside solar-like stars along their evolution. Recently, asteroseismic estimates of radial magnetic field amplitudes near the…

Solar and Stellar Astrophysics · Physics 2024-07-19 Shatanik Bhattacharya , Srijan Bharati Das , Lisa Bugnet , Subrata Panda , Shravan M. Hanasoge

We study a resistive tearing instability developing in a system evolving through the combined effect of Hall drift in the Electron-MHD limit and Ohmic dissipation. We explore first the exponential growth of the instability in the linear…

High Energy Astrophysical Phenomena · Physics 2016-09-19 Konstantinos N. Gourgouliatos , Rainer Hollerbach

We present the first numerical solutions of the coupled Einstein-Maxwell equations describing rapidly rotating neutron stars endowed with a magnetic field. These solutions are fully relativistic and self-consistent, all the effects of the…

General Relativity and Quantum Cosmology · Physics 2007-05-23 M. Bocquet , S. Bonazzola , E. Gourgoulhon , J. Novak