H-Functions in Radiative Transfer Theory: Calculation of Voigt Functions and Justification of a Model for Formation of Cyclotron Lines in the Spectra of Neutron Stars

Grigoryev, V. V.; Нагирнер, Д. И.; Грачев, С. И.

doi:10.1007/s10511-019-09569-4

Cited by 8 publications

(2 citation statements)

References 8 publications

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“…Because of that, a large fraction of X-ray luminosity produced by accretion columns is intercepted by the atmosphere of a NS. Reprocessing of X-ray radiation by the atmosphere results in the appearance of an absorption-like feature at the cyclotron energy corresponding to the local magnetic field strength [86,66]. In the case of magnetic field dominated by dipole component, the field strength at the NS surface is given by B = 0.5 B 0 √ 1 + 3 cos 2 θ , where B 0 is the field strength at the magnetic pole, and θ is co-latitude at the stellar surface.…”

Section: • Negative Correlationmentioning

confidence: 99%

Accreting strongly magnetised neutron stars: X-ray Pulsars

Mushtukov¹,

Tsygankov²

2022

Preprint

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X-ray pulsars (XRPs) are accreting strongly magnetised neutron stars (NSs) in binary systems with, as a rule, massive optical companions. Very reach phenomenology and high observed flux put them into the focus of observational and theoretical studies since first X-ray instruments were launched into space. The main attracting characteristic of NSs in this kind of systems is the magnetic field strength at their surface, about or even higher than 10 12 G, that is about six orders of magnitude stronger than what is attainable in terrestrial laboratories. Although accreting XRPs were discovered about 50 years ago, the details of the physical mechanisms responsible for their properties are still under debate. Here we review recent progress in observational and theoretical investigations of XRPs as a unique laboratory for studies of fundamental physics (plasma physics, QED and radiative processes) under extreme conditions of ultra-strong magnetic field, high temperature, and enormous mass density.

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Section: • Negative Correlationmentioning

confidence: 99%

Accreting strongly magnetised neutron stars: X-ray Pulsars

Mushtukov¹,

Tsygankov²

2022

Preprint

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“…X-ray emission from the side walls of the accretion column is expected to be largely beamed towards NS surface due to relativistic effects (Kaminker et al 1976;Lyubarskii & Syunyaev 1988). A fraction of X-ray emission is intercepted by the NS surface and reprocessed by its atmosphere (Poutanen et al 2013;Postnov et al 2015;Grigoryev et al 2019;Kylafis et al 2021). Reprocessed emission forms an additional part of the emission pattern.…”

Section: Introductionmentioning

confidence: 99%

Apparent luminosity and pulsed fraction affected by gravitational lensing of accretion columns in bright X-ray pulsars

Markozov,

Mushtukov

2023

Monthly Notices of the Royal Astronomical Society

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The luminosity of X-ray pulsars is their key parameter determining the geometry and physical conditions of the accretion flow both on the spatial scales of a binary system and on much smaller scales of emitting regions located close to the stellar surface. Traditionally, the luminosity of X-ray pulsars is estimated out of the X-ray energy flux averaged over the pulsed period and the estimated distance to the source. Due to the anisotropy of X-ray emission, the luminosity estimated on the base of the observed pulse profile can differ from the actual one. Super-critical X-ray pulsars with accretion columns are of particular interest because the X-ray flux from columns is a matter of strong gravitational lensing by a neutron star. Using toy model of an accretion column, we simulate beam patterns in super-critical X-ray pulsars, construct theoretical pulse profiles for different geometries and mutual orientations of pulsars and distant observers and show that despite strong light bending, the typical deviation of the apparent luminosity from the actual one is $\sim 20~{{\%}}$ only, and in $\sim 90~{{\%}}$ of cases, the apparent luminosity 0.8L ≲ Lapp ≲ 1.25L. However, the shape of the pulse profiles is strongly affected by the geometry of the emitting region. We show that the appearance and growth of accretion columns tend to be accompanied by an increase of observed pulsed fraction, which is in agreement with the recent observations of bright X-ray transients.

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Radiative Transfer Models

Efremenko

Kokhanovsky²

2021

Foundations of Atmospheric Remote Sensing

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H-Functions in Radiative Transfer Theory: Calculation of Voigt Functions and Justification of a Model for Formation of Cyclotron Lines in the Spectra of Neutron Stars

Cited by 8 publications

References 8 publications

Accreting strongly magnetised neutron stars: X-ray Pulsars

Accreting strongly magnetised neutron stars: X-ray Pulsars

Apparent luminosity and pulsed fraction affected by gravitational lensing of accretion columns in bright X-ray pulsars

Radiative Transfer Models

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