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Related papers: Soft X-ray Polarization in Thermal Magnetar Emissi…

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Within the magnetar scenario, the "twisted magnetosphere" model appears very promising in explaining the persistent X-ray emission from the Soft Gamma Repeaters and the Anomalous X-ray Pulsars (SGRs and AXPs). In the first two papers of the…

High Energy Astrophysical Phenomena · Physics 2015-05-13 S. Zane , N. Rea , R. Turolla , L. Nobili

The thermal emission of strongly magnetized neutron-star atmospheres is thought to be highly polarized. However, because of the different orientations of the magnetic field over the surface of the neutron star (NS), it is commonly assumed…

Astrophysics · Physics 2016-08-30 Jeremy S. Heyl , Nir J. Shaviv

High-energy data of accreting white dwarfs give access to the regime of the primary accretion-induced energy release and the different proposed accretion scenarios. We perform XMM-Newton observations of polars selected due to their ROSAT…

Solar and Stellar Astrophysics · Physics 2014-07-02 I. Traulsen , K. Reinsch , A. D. Schwope

We construct partially ionized hydrogen atmosphere models for magnetized neutron stars in radiative equilibrium with fixed surface fields between B=10^12 and 2x10^13 G and effective temperatures logT_eff=5.5-6.8, as well as with surface B…

Astrophysics · Physics 2009-06-23 Wynn C. G. Ho , Alexander Y. Potekhin , Gilles Chabrier

We construct radiative equilibrium models for strongly magnetized (B > 10^13 G) neutron-star atmospheres taking into account magnetic free-free absorption and scattering processes computed for two polarization modes. We include the effects…

Astrophysics · Physics 2009-11-06 Feryal Ozel

Magnetars are a unique class of neutron stars characterized by their incredibly strong magnetic fields. Unlike normal pulsars whose X-ray emission was driven by rotational energy loss, magnetars exhibit distinct X-ray emissions thought to…

High Energy Astrophysical Phenomena · Physics 2023-08-21 Che-Yen Chu , Hsiang-Kuang Chang

The properties of X-ray radiation from the polar caps predicted by the radio pulsar models depend on the surface chemical composition, magnetic field and star's mass and radius as well as on the cap temperature, size and position. Fitting…

Astrophysics · Physics 2008-02-03 G. G. Pavlov , V. E. Zavlin

We construct partially ionized hydrogen atmosphere models for magnetized neutron stars in radiative equilibrium with surface fields B=10^12-5 \times 10^14 G and effective temperatures T_eff \sim a few \times 10^5-10^6 K. These models are…

Astrophysics · Physics 2009-11-10 Wynn C. G. Ho , Dong Lai , Alexander Y. Potekhin , Gilles Chabrier

Observed X-ray spectra of some isolated magnetized neutron stars display absorption features, sometimes interpreted as ion cyclotron lines. Modeling the observed spectra is necessary to check this hypothesis and to evaluate neutron star…

Solar and Stellar Astrophysics · Physics 2009-07-03 V. F. Suleimanov , A. Y. Potekhin , K. Werner

In the last few years considerable observational resources have been devoted to study the thermal emission from isolated neutron stars. Detailed XMM and Chandra observations revealed a number of features in the X-ray pulse profile, like…

Astrophysics · Physics 2009-11-10 Silvia Zane , Roberto Turolla

Intense magnetic fields in the atmospheres of neutron stars render non-trivial angular dependence of intensity and polarization of soft X-ray emission originating from their surfaces. By tracking the complex electric field vector for each…

High Energy Astrophysical Phenomena · Physics 2026-03-17 Hoa Dinh Thi , Matthew G. Baring , Kun Hu , Alice K. Harding , Rachael E. Stewart , George A. Younes , Joseph A. Barchas

X-ray radiation from neutron stars manifests itself in a variety of settings. Isolated pulsars, and magnetars both exhibit quasi-thermal persistent soft X-ray emission from their surfaces. Transient magnetospheric bursts from magnetars and…

High Energy Astrophysical Phenomena · Physics 2025-02-21 Matthew G. Baring , Kun Hu , Hoa Dinh Thi

Pulsed non-thermal quiescent emission between 10 keV and around 150 keV has been observed in $\sim10$ magnetars. For inner magnetospheric models of such hard X-ray signals, resonant Compton upscattering of soft thermal photons from the…

High Energy Astrophysical Phenomena · Physics 2017-10-30 Zorawar Wadiasingh , Matthew G. Baring , Peter L. Gonthier , Alice K. Harding

We study several effects that influence the strength of the proton cyclotron and atomic features in the thermal spectra of magnetic neutron stars. We show that it is possible for vacuum polarization to strongly suppress the spectral lines…

Astrophysics · Physics 2009-11-10 Wynn C. G. Ho , Dong Lai

X-ray emission from the surface of isolated neutron stars (NSs) has been now observed in a variety of sources. The ubiquitous presence of pulsations clearly indicates that thermal photons either come from a limited area, possibly heated by…

High Energy Astrophysical Phenomena · Physics 2021-06-30 Davide De Grandis , Roberto Taverna , Roberto Turolla , Andrea Gnarini , Sergei B. Popov , Silvia Zane , Toby S. Wood

Abridged) We model the X-ray properties of millisecond pulsars (MSPs) by considering hot spot emission from a weakly magnetized rotating neutron star (NS) covered by an optically-thick hydrogen atmosphere. We investigate the limitations of…

Astrophysics · Physics 2009-11-13 Slavko Bogdanov , Jonathan E. Grindlay , George B. Rybicki

Magnetars are neutron stars with extremely high surface magnetic fields. They show diverse X-ray pulse profiles in the quiescent state. We perform a systematic Fourier analysis of their soft X-ray pulse profiles. We find that most magnetars…

High Energy Astrophysical Phenomena · Physics 2019-04-10 Chin-Ping Hu , C. -Y. Ng , Wynn C. G. Ho

Confronting theoretical models with observations of thermal radiation emitted by neutron stars is one of the most important ways to understand the properties of both, superdense matter in the interiors of the neutron stars and dense…

High Energy Astrophysical Phenomena · Physics 2015-12-25 A. Y. Potekhin , A. De Luca , J. A. Pons

Recent Chandra and XMM-Newton observations of a number of X-ray ``dim'' pulsating neutron stars revealed quite unexpected features in the emission from these sources. Their soft thermal spectrum, believed to originate directly from the star…

Astrophysics · Physics 2009-11-13 Silvia Zane , Roberto Turolla

(Abridged) We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X-ray data of ten magnetars, including canonical and transient anomalous X-ray pulsars (AXPs), and soft gamma repeaters (SGRs). In this…

Astrophysics · Physics 2009-11-13 Nanda Rea , Silvia Zane , Roberto Turolla , Maxim Lyutikov , Diego Gotz