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We present long-term (~10^4 M) axisymmetric simulations of differentially rotating, magnetized neutron stars in the slow-rotation, weak magnetic field limit using a perturbative metric evolution technique. Although this approach yields…

Astrophysics · Physics 2009-11-11 Zachariah B. Etienne , Yuk Tung Liu , Stuart L. Shapiro

The propeller regime of disk accretion to a rapidly rotating magnetized star is investigated here for the first time by axisymmetric 2.5D magnetohydrodynamic simulations. An expanded, closed magnetosphere forms in which the magnetic field…

We study the general-relativistic dynamics of matter being accreted onto and ejected by a magnetised and nonrotating neutron star. The dynamics is followed in the framework of fully general relativistic magnetohydrodynamics (GRMHD) within…

High Energy Astrophysical Phenomena · Physics 2022-09-21 Sercan Çıkıntoğlu , K. Yavuz Ekşi , Luciano Rezzolla

This study investigates the thermal stability of thin accretion disks in high-energy astrophysical systems, incorporating the effects of magnetic fields, winds, and coronae. We analyze how these factors influence disk stability, focusing on…

High Energy Astrophysical Phenomena · Physics 2025-01-28 Arezoo Tajmohamadi , Shahram Abbassi

The accretion-induced pulse-period changes of the Be/X-ray binary pulsar X Persei were investigated over a period of 1996 January to 2017 September. This study utilized the monitoring data acquired with the RXTE/ASM in 1.5$-$12 keV and…

High Energy Astrophysical Phenomena · Physics 2018-09-12 Fumiaki Yatabe , Kazuo Makishima , Tatehiro Mihara , Motoki Nakajima , Mutsumi Sugizaki , Shunji Kitamoto , Yuki Yoshida , Toshihiro Takagi

This review article summarizes two decades of laboratory research aimed at understanding the dynamics of accretion disks, with particular emphasis on magnetohydrodynamic experiments involving liquid metals and plasmas. First, the…

Solar and Stellar Astrophysics · Physics 2024-12-18 Christophe Gissinger

We have used a model of magnetic accretion to investigate the accretion flows of magnetic cataclysmic variables. Numerical simulations demonstrate that four types of flow are possible: discs, streams, rings and propellers. The fundamental…

Astrophysics · Physics 2009-11-13 A. J. Norton , O. W. Butters , T. L. Parker , G. A. Wynn

We performed 2D and full 3D magnetohydrodynamic simulations of disk accretion to a rotating star with an aligned or misaligned dipole magnetic field. We investigated the rotational equilibrium state and derived from simulations the ratio…

A three-dimensional numerical model for an accretion process investigation in the magnetosphere of a white dwarf in magnetic cataclysmic variables is developed. The model assumes that the white dwarf has a dipole magnetic field with its…

Solar and Stellar Astrophysics · Physics 2016-02-04 P. B. Isakova , A. G. Zhilkin , D. V. Bisikalo

We present in this proceeding some aspects of a model that should explain the spectral state changes observed in microquasars. In this model, ejection is assumed to take place only in the innermost disc region where a large scale magnetic…

Astrophysics · Physics 2007-05-23 P. O. Petrucci , J. Ferreira , S. Tricot , G. Pelletier , C. Cabanac , G. Henri

This paper examines the general relativistic model of a geometrically thick configuration of an accretion disc around an electrically charged black hole in an accelerated motion, as described by the C-metric family. We aim to study the…

High Energy Astrophysical Phenomena · Physics 2025-02-14 Shokoufe Faraji , Audrey Trova , Vladimir Karas

[Abridged] In order to explain the slow rotation observed in a large fraction of accreting pre-main-sequence stars (CTTSs), we explore the role of stellar winds in torquing down the stars. For this mechanism to be effective, the stellar…

Astrophysics · Physics 2009-11-13 Sean Matt , Ralph E. Pudritz

We present spectral calculations of non-LTE accretion disk models appropriate for high luminosity stellar mass black hole X-ray binary systems. We first use a dissipation profile based on scaling the results of shearing box simulations of…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Ted Tao , Omer Blaes

Magnetic damping induces the temporal and spatial decay of spin waves, characterized by the damping factor and attenuating length, both of which can be measured to determine various magnetic and spin-transport parameters. By investigating…

Mesoscale and Nanoscale Physics · Physics 2024-09-17 Peng-Bin He , Mikhail Cherkasskii

Thanks to long-term X-ray monitoring, a number of interacting binaries are now known to show X-ray periodicities on timescales of tens to hundreds of binary orbits. In some systems, precession of a warped accretion disc is the leading model…

High Energy Astrophysical Phenomena · Physics 2018-09-26 Kristen C. Dage , William I. Clarkson , Philip A. Charles , Silas G. T. Laycock , I-Chun Shih

We have developed a three-dimensional numerical model and applied it to simulate plasma flows in semi-detached binary systems whose accretor possesses a strong intrinsic magnetic field. The model is based on the assumption that the plasma…

Solar and Stellar Astrophysics · Physics 2010-10-26 A. G. Zhilkin , D. V. Bisikalo

When an accretion disk surrounds a binary rotating in the same sense, the binary exerts strong torques on the gas. Analytic work in the 1D approximation indicated that these torques sharply diminish or even eliminate accretion from the disk…

High Energy Astrophysical Phenomena · Physics 2015-07-15 Ji-Ming Shi , Julian H. Krolik

Classical T Tauri stars (CTTSs) are young stellar objects that accrete materials from their accretion disc influenced by their strong magnetic field. The magnetic pressure truncates the disc at a few stellar radii and forces the material to…

Solar and Stellar Astrophysics · Physics 2022-11-30 Kim Pouilly , Oleg Kochukhov , Ágnes Kóspál , Axel Hahlin , Andres Carmona , Péter Ábrahám

The long white-dwarf spin periods in the magnetic cataclysmic variables EX Hya and V1025 Cen imply that if the systems possess accretion discs then they cannot be in equilibrium. It has been suggested that instead they are discless…

Astrophysics · Physics 2016-08-30 Coel Hellier , Graham Wynn , David Buckley

Currently, two competing models are invoked in order to explain the observable properties of Anomalous X-ray Pulsars (AXPs). One model assumes that AXP emission is powered by a strongly magnetized neutron star - i.e., a magnetar. Other…

Astrophysics · Physics 2007-05-23 G. J. Francischelli , R. A. M. J. Wijers