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Related papers: GRMHD Simulations of Accreting Neutron Stars with …

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Accreting neutron stars differ from black holes by the presence of the star's own magnetic field, whose interaction with the accretion flow is a central component in understanding these systems' disk structure, outflows, jets, and spin…

High Energy Astrophysical Phenomena · Physics 2023-11-09 Kyle Parfrey , Alexander Tchekhovskoy

The pulsed X-ray emission from the neutron star surface acts as a window to study the state of matter in the neutron star interior. For accreting millisecond pulsars, the surface X-ray emission is generated from the `hotspots' formed due to…

High Energy Astrophysical Phenomena · Physics 2025-05-20 Pushpita Das , Tuomo Salmi , Jordy Davelaar , Oliver Porth , Anna Watts

Disk accretion to rotating stars with complex magnetic fields is investigated using full three-dimensional magnetohydrodynamic (MHD) simulations. The studied magnetic configurations include superpositions of misaligned dipole and quadrupole…

Astrophysics · Physics 2009-11-13 M. Long , M. M. Romanova , R. V. E. Lovelace

Disc accretion to a rotating star with a non-dipole magnetic field is investigated for the first time in full three-dimensional (3D) magnetohydrodynamic (MHD) simulations. We investigated the cases of (1) pure dipole, (2) pure quadrupole,…

Astrophysics · Physics 2008-11-26 M. Long , M. M. Romanova , R. V. E. Lovelace

Disk-fed accretion onto neutron stars can power a wide range of astrophysical sources ranging from X-ray binaries, to accretion powered millisecond pulsars, ultra-luminous X-ray sources, and gamma-ray bursts. A crucial parameter controlling…

High Energy Astrophysical Phenomena · Physics 2023-11-17 Ariadna Murguia-Berthier , Kyle Parfrey , Alexander Tchekhovskoy , Jonatan Jacquemin-Ide

Neutron stars and black holes in X-ray binaries are observed to host strong collimated jets in the hard spectral state. Numerical simulations can act as a valuable tool in understanding the mechanisms behind jet formation and its…

High Energy Astrophysical Phenomena · Physics 2023-12-15 Pushpita Das , Oliver Porth

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

Accreting neutron stars can power a wide range of astrophysical phenomena including short- and long-duration gamma-ray bursts, ultra-luminous X-ray sources, and X-ray binaries. Numerical simulations are a valuable tool for studying the…

High Energy Astrophysical Phenomena · Physics 2018-01-08 Kyle Parfrey , Alexander Tchekhovskoy

Accreting pulsars power relativistic jets, and display a complex spin phenomenology. These behaviours may be closely related to the large-scale configuration of the star's magnetic field, shaped by its interaction with the surrounding…

High Energy Astrophysical Phenomena · Physics 2017-06-21 Kyle Parfrey , Anatoly Spitkovsky , Andrei M. Beloborodov

We perform MHD simulations of a thin resistive and viscous accretion disk around a neutron star with the surface dipolar magnetic field of 10$^8$ Gauss. The system evolution is followed during the interval of 500 millisecond pulsar…

High Energy Astrophysical Phenomena · Physics 2018-02-02 M. Čemeljić , V. Parthasarathy , W. Kluźniak

The appearance and time variability of accreting millisecond X-ray pulsars (hereafter AMXPs, e.g. Wijnands & van der Klis 1998) depends strongly on the accretion rate, the effective viscosity and the effective magnetic diffusivity of the…

Astrophysics · Physics 2009-11-13 Marina M. Romanova , Akshay K. Kulkarni , Min Long , Richard V. E. Lovelace

By performing 2.5-dimensional general relativistic radiation magnetohydrodynamic simulations, we demonstrate supercritical accretion onto a non-rotating, magnetized neutron star, where the magnetic field strength of dipole fields is…

High Energy Astrophysical Phenomena · Physics 2017-08-23 Hiroyuki R. Takahashi , Ken Ohsuga

Although ultraluminous X-ray pulsars (ULXPs) are believed to be powered by super-Eddington accretion onto a magnetized neutron star (NS), the detailed structures of the inflow-outflow and magnetic fields are still not well understood. We…

High Energy Astrophysical Phenomena · Physics 2024-10-24 Akihiro Inoue , Ken Ohsuga , Hiroyuki R. Takahashi , Yuta Asahina , Matthew J. Middleton

We investigate the long-term evolution of black hole accretion disks formed in neutron star mergers. These disks expel matter that contributes to an $r$-process kilonova, and can produce relativistic jets powering short gamma-ray bursts.…

High Energy Astrophysical Phenomena · Physics 2018-11-07 Rodrigo Fernández , Alexander Tchekhovskoy , Eliot Quataert , Francois Foucart , Daniel Kasen

We show results of global 3D MHD simulations of accretion onto stars with superposition of the dipole and octupole fields, where we vary the ratio between components. Simulations show that if octupolar field strongly dominates at the…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Min Long , Marina M. Romanova , Frederick K. Lamb

The conventional picture of disk accretion onto magnetized neutron stars has been challenged by the spin changes observed in a few X-ray pulsars, and by theoretical results from numerical simulations of disk-magnetized star interactions.…

Astrophysics · Physics 2009-11-11 Hai-Lang Dai , Xiang-Dong Li

We present a 3-D ideal MHD simulation of magnetospheric accretion onto a non-rotating star. The accretion process unfolds with intricate 3-D structures driven by various mechanisms. First, the disc develops filaments at the magnetospheric…

Solar and Stellar Astrophysics · Physics 2023-12-18 Zhaohuan Zhu , James M. Stone , Nuria Calvet

The merger of binary neutron stars, or of a neutron star and a stellar-mass black hole, can result in the formation of a massive rotating torus around a spinning black hole. In addition to providing collimating media for gamma-ray burst…

High Energy Astrophysical Phenomena · Physics 2017-12-13 Daniel M. Siegel , Brian D. Metzger

It is widely assumed that the observed reduction of the magnetic field of millisecond pulsars can be connected to the accretion phase during which the pulsar is spun up by mass accretion from a companion. A wide variety of reduction…

Astrophysics · Physics 2016-11-15 Matthias Vigelius , Donald Payne , Andrew Melatos

In this paper we present the results of time-dependent simulations of dipolar axisymmetric magnetospheres of neutron stars carried out both within the framework of relativistic magnetohydrodynamics and within the framework of resistive…

Astrophysics · Physics 2009-11-13 S. S. Komissarov
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