Related papers: On the torque exerted by a warped, magnetically th…
We numerically investigate the hydrodynamics of accretion disk reversal and relate our findings to the observed spin-rate changes in the accreting X-ray pulsar GX~1+4. In this system, which accretes from a slow wind, the accretion disk…
There are X-ray pulsating sources that are explained by accretion from disks around neutron stars. Such disks deserve a detailed analysis. In particular, the dipole magnetic field of the central star may penetrate the disk, giving rise to…
We consider the accretion process in a disk with magnetic fields that are dragged in from the interstellar medium by gravitational collapse. Two diffusive processes are at work in the system: (1) "viscous" torques exerted by turbulent and…
The nature of the 5-12 s "anomalous" X-ray pulsars remains a mystery. Among the models that have been proposed to explain the properties of AXPs, the most likely ones are: (1) isolated accreting neutron stars evolved from the…
We develop an effective model for a neutron star with a magnetosphere. It takes into account the electromagnetic torques acting on the magnetic dipole, the friction forces between the crust and the core, and the gravitational corrections.…
We present a detailed analysis of the properties of twisted, force-free magnetospheres of non-rotating neutron stars, which are of interest in the modelling of magnetar properties and evolution. In our models the magnetic field smoothly…
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…
Assuming the wind-fed accretion magnetars in long period X-ray pulsars, we calculated the rotational evolution of the neutron stars. Our calculations considered the effects of the magnetic field decay in magnetars. The results show that…
Accretion of matter onto a magnetic, rotating object can be strongly affected by the interaction with its magnetic field. This occurs in a variety of astrophysical settings involving young stellar objects, white dwarfs, and neutron stars.…
The evolutionary scenario of the neutron star magnetic field is examined assuming a spindown-induced expulsion of magnetic flux originally confined to the core, in which case the expelled flux undergoes ohmic decay. The nature of field…
We study the magnetic interaction between a neutron star and its disk by solving the time-dependent relativistic force-free equations. At the initial state, we assume that the dipole magnetic field of the neutron star connects the neutron…
Neutron stars are strongly magnetized rotating compact objects. Therefore they also produce huge electric fields accelerating particles to ultra-relativistic energies. The simplest magnetic topology is a dipole traditionally located at the…
We study the spin-up of the accreting neutron stars with a realistic hyperon-softened equation of state. Using precise 2-D calculations we study the evolutionary tracks of accreting neutron stars in the angular-momentum - frequency plane.…
The majority of solar-type stars reside in multiple systems, especially binaries. They form in dense cores of molecular clouds that are observed to be significantly magnetized. Our previous study shows that magnetic braking can tighten the…
The quasiperiodic oscillations found in the three giant flares of soft gamma-ray repeaters observed to date have been interpreted as crustal oscillations caused by a starquake following a dramatic rearrangement of the stellar magnetic…
Protoplanetary disk evolution exhibits trends with stellar mass, but also diversity of structure, and lifetime, with implications for planet formation and demographics. We show how varied outcomes can result from evolving structures in the…
Tight and compact binary systems, such as double neutron star binaries, are believed to undergo a common envelope evolution phase, resulting in strongly bound orbits. During this phase, the outer layers of the primary star are expelled,…
We conduct force-free simulations of a single neutron star undergoing orbital motion in flat spacetime, mimicking the trajectory of the star about the center of mass on a compact binary system. Our attention is focused on the kinetic energy…
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…
Most of ultraluminous X-ray sources are thought to be objects accreting above their Eddington limits. In the recently identified class of ultraluminous X-ray pulsars, accretor is a neutron star and thus has a fairly small mass with a small…