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Quasi-spherical subsonic accretion onto slowly rotating magnetized NS is considered, when the accreting matter settles down subsonically onto the rotating magnetosphere, forming an extended quasi-static shell. The shell mediates the angular…

High Energy Astrophysical Phenomena · Physics 2013-10-24 N. I. Shakura , K. A. Postnov , A. Yu. Kochetkova , L. Hjalmarsdotter

A theoretical model for quasi-spherical subsonic accretion onto slowly rotating magnetized neutron stars is constructed. In this model the accreting matter subsonically settles down onto the rotating magnetosphere forming an extended…

High Energy Astrophysical Phenomena · Physics 2015-05-30 N. Shakura , K. Postnov , A. Kochetkova , L. Hjalmarsdotter

Quasi-spherical accretion in wind-fed X-ray pulsars is discussed. At X-ray luminosities <4 10^{36} erg/s, a hot convective shell is formed around the neutron star magnetosphere, and subsonic settling accretion regime sets in. In this…

High Energy Astrophysical Phenomena · Physics 2011-11-08 K. Postnov , N. Shakura , A. Kochetkova , L. Hjalmarsdotter

The theory of quasi-spherical subsonic accretion onto magnetized rotating neutron star is reviewed. Different regimes of quasi-spherical accretion onto a neutron star: supersonic (Bondi) accretion, which takes place when the captured matter…

High Energy Astrophysical Phenomena · Physics 2019-02-22 N. Shakura , K. Postnov

A review of wind accretion in high-mass X-ray binaries is presented. We focus attention to different regimes of quasi-spherical accretion onto the neutron star: the supersonic (Bondi) accretion, which takes place when the captured matter…

High Energy Astrophysical Phenomena · Physics 2015-06-16 N. I. Shakura , K. A. Postnov , A. Yu. Kochetkova , L. Hjalmarsdotter

A review of wind accretion in HMXB is presented. We focus on different regimes of quasi-spherical accretion onto a NS: supersonic (Bondi) accretion, which takes place when the captured matter cools down rapidly and falls supersonically…

High Energy Astrophysical Phenomena · Physics 2015-07-16 N. I. Shakura , K. A. Postnov , A. Yu. Kochetkova , L. Hjalmarsdotter , L. Sidoli , A. Paizis

The properties of wind accretion in symbiotic X-ray binaries (SyXBs) consisting of red-giant and magnetized neutron star (NS) are discussed. The spin-up/spin-down torques applied to NS are derived based on a hydrodynamic theory of…

High Energy Astrophysical Phenomena · Physics 2011-10-07 K. Postnov , N. Shakura , A. González-Galán , E. Kuulkers , P. Kretschmar , S. Larsson , M. H. Finger , A. Kochetkova , G. Lü , L. Yungelson

Features and applications of quasi-spherical settling accretion onto rotating magnetized neutron stars in high-mass X-ray binaries are discussed. The settling accretion occurs in wind-fed HMXBs when the plasma cooling time is longer than…

High Energy Astrophysical Phenomena · Physics 2017-01-03 Konstantin Postnov , Lida Oskinova , Jose Miguel Torrejón

Neutron stars in high-mass X-ray binaries (HMXBs) generally accrete from the wind matter of their massive companion stars. Recently Shakura et al. (2012) suggested a subsonic accretion model for low-luminosity ($<4\times 10^{36}$…

High Energy Astrophysical Phenomena · Physics 2016-06-29 Tao Li , Yong Shao , Xiang-Dong Li

The appearance of subsonic propellers situated in a strong wind is discussed. We show that it is similar to the appearance of anomalous X-ray pulsars (AXPs) provided the mass and the magnetic moment of neutron stars are 1.4 solar masses,…

Astrophysics · Physics 2009-11-10 N. R. Ikhsanov , C. -S. Choi

We elaborate on a recently proposed model for subsonic quasi-spherical accretion onto slowly rotating pulsars, in which accretion is mediated through a hot quasi-static shell above the neutron star magnetosphere. We show that under the same…

High Energy Astrophysical Phenomena · Physics 2015-06-11 N. Shakura , K. Postnov , L. Hjalmarsdotter

We investigate further a model of the accreting millisecond X-ray pulsars we proposed earlier. In this model, the X-ray-emitting regions of these pulsars are near their spin axes but move. This is to be expected if the magnetic poles of…

X-ray pulsars shine thanks to the conversion of the gravitational energy of accreted material to X-ray radiation. The accretion rate is modulated by geometrical and hydrodynamical effects in the stellar wind of the pulsar companions and/or…

High Energy Astrophysical Phenomena · Physics 2018-04-25 Roland Walter , Carlo Ferrigno

Study of observed spin evolution of long-period X-ray pulsars challenges quasi-spherical and Keplerian disk accretion scenarios. It suggests that the magnetospheric radius of the neutron stars is substantially smaller than Alfven radius and…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Nazar Ikhsanov , Nina Beskrovnaya , Yury Likh

We present a new model of the population of symbiotic X-ray binaries (SyXBs) that takes into account non-stationary character of quasi-spherical sub-sonic accretion of the red giant's stellar wind onto slowly rotating neutron stars. Updates…

High Energy Astrophysical Phenomena · Physics 2019-02-19 Lev Yungelson , Alexandre Kuranov , Konstantin Postnov

At steady low-luminosity states, Supergiant Fast X-ray Transients (SFXTs) can be at the stage of quasi-spherical settling accretion onto slowly rotating magnetized NS from the OB-companion winds. At this stage, a hot quasi-static shell is…

High Energy Astrophysical Phenomena · Physics 2014-06-24 N. Shakura , k. Postnov , L. Sidoli , A. Paizis

The wind-fed accretion of gas with an intrinsic magnetic field onto neutron stars in high-mass X-ray binaries (HMXBs) is discussed. The criteria for the implementation of quasi-spherical accretion in the system, the formation of a Keplerian…

High Energy Astrophysical Phenomena · Physics 2025-07-17 N. R. Ikhsanov , M. Yu. Piotrovich , N. G. Beskrovnaya

Strong magnetic field of accreting neutron stars ($10^{14}$ G) is hard to probe by X-ray spectroscopy but can be indirectly inferred from spin-up/spin-down measurement in X-ray pulsars. The existing observations of slowly rotating X-ray…

High Energy Astrophysical Phenomena · Physics 2015-06-16 K. A. Postnov , N. I. Shakura , A. Yu. Kochetkova , L. Hjalmarsdotter

Millisecond x-ray pulsars have weak magnetic dipole moments of $\sim 10^{16}$\,T\,m$^3$ compared to ordinary X-ray pulsars with dipole moments of $10^{20}$\,T\,m$^3$. For this reason a surrounding accretion disc can extend closer to the…

High Energy Astrophysical Phenomena · Physics 2010-11-12 Solomon Belay Tessema , Ulf Torkelsson

Three high-mass X-ray binaries have been discovered recently exhibiting enormous spinup rates. Conventional accretion theory predicts extremely high surface dipolar magnetic fields that we believe are unphysical. Instead, we propose quite…

High Energy Astrophysical Phenomena · Physics 2018-06-06 D. M. Christodoulou , S. G. T. Laycock , D. Kazanas
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