Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Centaurus X-3

Kraus, Ute; Blum, S. E.; Schulte, J.; Ruder, H.; Meszaros, P.

doi:10.1086/177653

Cited by 41 publications

(61 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Cen X-3 was the first accreting X-ray pulsar to which the decomposition method was applied (Kraus et al 1996) and for which a distorted geometry with a small offset δ was found. The derived beam patterns are a combination of a pencil and fan beam.…”

Section: Discussionmentioning

confidence: 99%

“…Based on the assumption of distorted magnetic fields, Kraus et al (1995) developed the decomposition method that allows us to find two symmetric contributions from the two poles to the observed total pulse profiles. Using this pulse profile decomposition method, we have successfully analysed the pulse profiles of the X-ray pulsars Cen X-3 (Kraus et al 1996), Her X-1 (Blum & Kraus 2000), EXO 2030+375 (Sasaki et al 2010), and A 0535+26 (Caballero et al 2011).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Analysing X-ray pulsar profiles

Sasaki¹,

Müller²,

Kraus³

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

Aims. By analysing the asymmetric pulse profiles of the transient Be/X-ray binaries 4U 0115+63 and V 0332+53 we aim to identify the origin of the pulsed emission to understand the geometry of the accretion onto the neutron star. Methods. We have applied the pulse-profile decomposition method, which enabled us to find two symmetric pulse profiles for the two magnetic poles of the neutron star. We derived beam patterns for different energy bands and luminosity states. This allowed us to identify the components that are responsible for the emission. The analysis and the models used for the interpretation of the results take relativistic light deflection into account. Results. We find that the magnetic field of the neutron star is distorted in both 4U 0115+63 and V 0332+53. The beam patterns are interpreted in terms of a model for an accretion column that includes the formation of a halo at the bottom of the accretion column and scattering in the upper accretion stream. Conclusions. In both systems, an accretion column forms while the accretion rate is high. If the accretion decreases and the sources become fainter, the emission from the halo and the accretion column disappears. In 4U 0115+63 there seems to be significant scattering of photons in the still existing accretion stream even at the end of the outburst. In V 0332+53, the scattering in the upper stream also disappears at the end and we apparently observe the emission from the hot spots on the neutron star.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysing X-ray pulsar profiles

Sasaki¹,

Müller²,

Kraus³

et al. 2012

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…Kraus et al (1996) analyzed the pulse profiles of Cen X-3 and reconstructed the geometry and beam pattern for this object. They found that the most likely inclination angles of the magnetic axis to the rotation axis are ∼20…”

Section: Discussionmentioning

confidence: 99%

A puzzling paucity of double peaked X-ray pulsars

Bulik

Gondek-Rosińska

Santangelo³

et al. 2003

A&A

View full text Add to dashboard Cite

Abstract. Accretion powered pulsars exhibit a variety of lightcurves. In this paper we propose to classify the observed lightcurves as single or double pulsed. We analyze the lightcurves of 89 accretion powered pulsars and assign them to these classes. We present three datasets: first in which the classification can be easily done, second for which the classification is more difficult and not certain, and third for which we were unable to classify the pulsar because of a lack of published data. We analyze a simple model in which the angles between the magnetic and rotation axis β, and between the rotation axis and the line of sight θ are random, and show that it is inconsistent with the data. We also present a model in which the angle between the magnetic axis and the rotation axis is restricted and compare it with the data. This leads to an upper limit on the angle β < 50• . We conclude that there must be a mechanism that leads to alignment of the magnetic and spin axis in X-ray pulsars.Key words. X-rays: star -stars: neutron The lightcurves of accretion powered X-ray pulsarsAccreting neutron stars were discovered more than 30 years ago (Shklovsky 1967), with Cen X-3 beeing the first one discovered that showed pulsations (Giacconi et al. 1971). Currently we know nearly one hundred accreting neutron stars, and in more than eighty of them pulsations were identified (Liu et al. 2000(Liu et al. , 2001. Accreting neutron stars in binaries exhibit a wide range of X-ray light curves. They vary as a function of the photon energy, and moreover in the transient sources the pulse shapes change with the variation of the luminosity. The pulse period in accreting sources is identified with the rotation of a magnetized star. As the matter from the companion star falls onto the neutron star it is channeled onto the magnetic poles by the strong magnetic field of the neutron star. Thus the polar caps and/or accretion columns are the places where most of the emission takes place. Several theoretical models of radiation of magnetized accretion powered neutron stars have been proposed and the beam shape is usually described in terms of pencil beams, when most of the radiation is emitted along the magnetic field, or fan beams when most of the radiation is emitted perpendicularly to the magnetic field.The magnetized radiative transfer is solved using a difference scheme (Meszaros & Nagel 1985;Bulik et al. 1992), or using Monte Carlo scheme (Lamb et al. 1990; Send offprint requests to: T. Bulik, e-mail: bulik@camk.edu.pl Isenberg et al. 1998), for a review see . In the pencil beam model radiation from each polar cap produces one pulse in the light curve. Depending on the emission cap physics and the strength of the magnetic field each pulse may have some additional structure. When during the rotation of an accreting pulsar we see two polar caps the lightcurve should exhibit two distinct pulses (peaks), and if only one cap is seen then the lightcurve is single peaked. In the case of dominant radiation from the accretion column (fan ...

show abstract

“…Detailed models for the emission pattern of XRBs, which include relativistic light propagation (Kraus et al 1996;Blum & Kraus 2000), as well as the statistical analysis of accreting neutron star pulse profiles (Bulik et al 2003), however, imply β < ∼ 20…”

Section: Crsf Variabilitymentioning

confidence: 99%

The variable cyclotron line in GX 301-2

Kreykenbohm

Wilms

Coburn

et al. 2004

A&A

View full text Add to dashboard Cite

Abstract. We present pulse phase resolved spectra of the hypergiant high mass X-ray binary GX 301−2. We observed the source in 2001 October with RXTE continuously for a total on-source time of almost 200 ks. We model the continuum with both, a heavily absorbed partial covering model and a reflection model. In either case we find that the well known cyclotron resonant scattering feature (CRSF) at ∼35 keV is -although present at all pulse phases -strongly variable over the pulse: the line position varies by 25% from 30 keV in the fall of the secondary pulse to 38 keV in the fall of the main pulse where it is deepest. The line variability implies that we are seeing regions of magnetic field strength varying between 3.4 × 10 12 G and 4.2 × 10 12 G.

show abstract

Analyzing X-Ray Pulsar Profiles: Geometry and Beam Pattern of Centaurus X-3

Cited by 41 publications

References 0 publications

Analysing X-ray pulsar profiles

Analysing X-ray pulsar profiles

A puzzling paucity of double peaked X-ray pulsars

The variable cyclotron line in GX 301-2

Contact Info

Product

Resources

About