Timing and Spectroscopy of Accreting X-ray Pulsars: the State of Cyclotron Line Studies

Heindl, W. A.; Rothschild, R. E.; Coburn, W.; Staubert, R.; Wilms, J.; Kreykenbohm, I.; Kretschmar, P.

doi:10.1063/1.1781049

Cited by 22 publications

(16 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Contrary to other classes of X-ray pulsars, in which it has been possible to infer B p from the detection of (electron) cyclotron lines in their spectra 63 (see e.g Ref. 64 for a review), up to now spin-down remains the only way for SGRs/AXPS, with all the ensuing uncertainties (chiefly the fact that spin-down is indeed due to…”

Section: Low-magnetic-field Magnetars: Alternative Scenariosmentioning

confidence: 97%

Low-Magnetic-Field Magnetars

Turolla

Esposito

2013

Int. J. Mod. Phys. D

View full text Add to dashboard Cite

It is now widely accepted that soft gamma repeaters and anomalous X-ray pulsars are the observational manifestations of magnetars, i.e. sources powered by their own magnetic energy. This view was supported by the fact that these "magnetar candidates" exhibited, without exception, a surface dipole magnetic field (as inferred from the spin-down rate) in excess of the electron critical field (≃ 4.4×10^13 G). The recent discovery of fully qualified magnetars, SGR 0418+5729 and Swift J1822.3-1606, with dipole magnetic field well in the range of ordinary radio pulsars posed a challenge to the standard picture, showing that a very strong field is not necessary for the onset of magnetar activity (chiefly bursts and outbursts). Here we summarize the observational status of the low-magnetic-field magnetars and discuss their properties in the context of the mainstream magnetar model and its main alternatives

show abstract

Section: Low-magnetic-field Magnetars: Alternative Scenariosmentioning

confidence: 97%

Low-Magnetic-Field Magnetars

Turolla

Esposito

2013

Int. J. Mod. Phys. D

View full text Add to dashboard Cite

show abstract

“…Harmonics of the CRSFs are also seen in several sources: for example up to the fifth harmonic in 4U 0115+63 [14,15], two harmonics in V 0332+53 [16], and a single harmonic in several sources like Vela X-1 [17], A 0535+26 [18] and 4U 1538-52 [19]. [20] has reported the presence of two independent sets of fundamental CRSF in 4U 0115-63, possibly originating from spatially distinct emitting regions.…”

Section: Crsfs and Harmonics: Current Censusmentioning

confidence: 99%

Cyclotron Lines: From Magnetic Field Strength Estimators to Geometry Tracers in Neutron Stars

Maitra

2017

J Astrophys Astron

View full text Add to dashboard Cite

With exactly forty years since the discovery of the first cyclotron line in Her X-1, there have been remarkable advancements in the field related to study of the physics of accreting neutron stars -cyclotron lines have been a major torchbearer in this regard, from being the only direct estimator of the magnetic field strength, a tracer of accretion geometry and an indicator of the emission beam in these systems. The main flurry of activities have centred around studying the harmonic separations, luminosity dependence, pulse phase dependence and more recently the shapes of the line and the trend for long term evolution in the line energy. This article visits the important results related to cyclotron lines since its discovery and reviews their significance. An emphasis is laid on pulse phase resolved spectroscopy and the important clues a joint timing and spectral study in this context can provide, to build a complete picture for the physics of accretion and hence X-ray emission in accreting neutron stars.

show abstract

“…The observations suggest that the absorption occurs in accretion columns near the NS surface. The absorption features vary with NS spin-phase (Heindl et al 2004), and these variations have been modeled for various accretion geometries, magnetic field configurations, and viewing angles (e.g., Mukherjee & Bhattacharya 2012). The hard spectra of the accreting NSs -due to high temperatures in the accretion column -allow detection of multiple cyclotron harmonics in some cases (e.g., Santangelo et al 1999).…”

Section: Introductionmentioning

confidence: 99%

Possible Phase-dependent Absorption Feature in the X-Ray Spectrum of the Middle-aged PSR J0659+1414

Arumugasamy

Kargaltsev

Posselt

et al. 2018

ApJ

View full text Add to dashboard Cite

We report on the energy-resolved timing and phase-resolved spectral analysis of X-ray emission from PSR J0659+1414 observed with XMM-Newton and NuSTAR. We find that the new data rule out the previously suggested model of the phase-dependent spectrum as a three-component (2 blackbodies + power-law) continuum, which shows large residuals between 0.3 − 0.7 keV. Fitting neutron star atmosphere models or several blackbodies to the spectrum does not provide a better description of the spectrum, and requires spectral model components with unrealistically large emission region sizes. The fits improve significantly if we add a phase-dependent absorption feature with central energy 0.5 − 0.6 keV and equivalent width up to ≈ 50 eV. We detected the feature for about half of the pulse cycle. Energy-resolved pulse profiles support the description of the spectrum with a three-component continuum and an absorption component. The absorption feature could be interpreted as an electron cyclotron line originating in the pulsar magnetosphere and broadened by the non-uniformity of magnetic field along the line of sight. The significant phase-variability in the thermal emission from the entire stellar surface may indicate multi-polar magnetic fields and a nonuniform temperature distribution. The strongly pulsed non-thermal spectral component detected with NuSTAR in the 3-20 keV range is well fit by a power-law model with a photon index Γ = 1.5 ± 0.2.

show abstract

Timing and Spectroscopy of Accreting X-ray Pulsars: the State of Cyclotron Line Studies

Cited by 22 publications

References 22 publications

Low-Magnetic-Field Magnetars

Low-Magnetic-Field Magnetars

Cyclotron Lines: From Magnetic Field Strength Estimators to Geometry Tracers in Neutron Stars

Possible Phase-dependent Absorption Feature in the X-Ray Spectrum of the Middle-aged PSR J0659+1414

Contact Info

Product

Resources

About