scholarly journals Physical Environment of Accreting Neutron Stars

2016 ◽  
Vol 2016 ◽  
pp. 1-15
Author(s):  
J. Wang
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Strong Magnetic Field ◽  
Physical Environment ◽  
Binary Systems ◽  
High Mass ◽  
Physical Processes ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

Neutron stars (NSs) powered by accretion, which are known as accretion-powered NSs, always are located in binary systems and manifest themselves as X-ray sources. Physical processes taking place during the accretion of material from their companions form a challenging and appealing topic, because of the strong magnetic field of NSs. In this paper, we review the physical process of accretion onto magnetized NS in X-ray binary systems. We, firstly, give an introduction to accretion-powered NSs and review the accretion mechanism in X-ray binaries. This review is mostly focused on accretion-induced evolution of NSs, which includes scenario of NSs both in high-mass binaries and in low-mass systems.

scholarly journals Accreting Neutron Stars

1987 ◽  
Vol 125 ◽  
pp. 135-148
Author(s):  
N.E. White
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Neutron Stars ◽  
Magnetic Field Strength ◽  
Spectral Properties ◽  
High Mass ◽  
X Ray ◽  
Temporal Properties ◽  
Low Mass ◽  
X Ray Binaries

This paper reviews accreting neutron stars in X-ray binaries, with particular emphasis on how variations in magnetic field strength may be responsible for explaining the spectral and temporal properties observed from the various systems. This includes a review of X-ray pulsars in both low and high mass systems, and a discussion of the spectral properties of the low mass X-ray binaries.

scholarly journals Jets in the soft state in Cyg X-3 caused by advection of the donor magnetic field and unification with low-mass X-ray binaries

2019 ◽  
Vol 492 (1) ◽  
pp. 223-231 ◽  
Author(s):  
Xinwu Cao ◽  
Andrzej A Zdziarski
Keyword(s):  
Magnetic Field ◽  
High Mass ◽  
Vertical Magnetic Field ◽  
Subsequent Formation ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Low Mass ◽  
X Ray Binaries

ABSTRACT The high-mass accreting binary Cyg X-3 is distinctly different from low-mass X-ray binaries (LMXBs) in having powerful radio and γ-ray emitting jets in its soft spectral state. However, the transition from the hard state to the soft one is first associated with quenching of the hard-state radio emission, as in LMXBs. The powerful soft-state jets in Cyg X-3 form, on average, ∼50 d later. We interpret the initial jet quenching as due to the hard-state vertical magnetic field quickly diffusing away in the thin disc extending to the innermost stable circular orbit in the soft state, or, if that field is produced in situ, also cessation of its generation. The subsequent formation of the powerful jets occurs due to advection of the magnetic field from the donor. We find this happens only above certain threshold accretion rate associated with appearance of magnetically driven outflows. The ∼50 d lag is of the order of the viscous time-scale in the outer disc, while the field advection is much faster. This process does not happen in LMXBs due to the magnetic fluxes available from their donors being lower than that for the wind accretion from the Wolf–Rayet donor of Cyg X-3. In our model, the vertical magnetic field in the hard state, required to form the jets both in Cyg X-3 and LMXBs, is formed in situ rather than advected from the donor. Our results provide a unified scenario of the soft and hard states in both Cyg X-3 and LMXBs.

scholarly journals Observations of Low Mass X-Ray Binaries

1996 ◽  
Vol 158 ◽  
pp. 349-358
Author(s):  
Alan P. Smale
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Binary Systems ◽  
Light Curves ◽  
X Ray ◽  
Fast Timing ◽  
Low Mass ◽  
And Behavior ◽  
X Ray Binaries

AbstractIn this paper I review the properties and behavior of low-mass X-ray binary systems (LMXBs) that contain neutron stars (NS), concentrating on the Galactic bulge sources and bursters. I describe the observed characteristics of LMXBs including their light curves, spectra, eclipses, dips, bursts, flares, pulsations, QPO, long-term periodicities and orbital period changes, and explain how fast timing results and the distinction between ‘Z’ and ‘atoll’-type sources provide the key to a unified model of LMXB behavior.

scholarly journals Probability Distribution of Magnetic Field Strengths through the Cyclotron Lines in High-Mass X-ray Binaries

2020 ◽  
Vol 13 (3) ◽  
pp. 243-251
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Accretion Rate ◽  
High Mass ◽  
X Ray ◽  
Different Types ◽  
The Difference ◽  
Field Formation ◽  
X Ray Binaries ◽  
The Magnetic Field

Abstract: The study of variation of measured cyclotron lines is of fundamental importance to understand the physics of the accretion process in magnetized neutron star systems. We investigate the magnetic field formation, evolution and distribution for several High- Mass X-ray Binaries (HMXBs). We focus our attention on the cyclotron lines that have been detected in HMXB classes in their X-ray spectra. As has been correctly pointed out, several sources show variation in cyclotron lines, which can result due to the effect of accretion dynamics and hence that would reflect the magnetic field characteristics. Besides, the difference in time scales of variation of accretion rate and different types of companion can be used to distinguish between magnetized neutron stars. Keywords: Stars: neutron stars, High-Mass X-ray binaries, Stars: magnetic field, Cyclotron lines.

scholarly journals Low-Mass X-ray Binaries—Recent Developments

1996 ◽  
Vol 165 ◽  
pp. 301-312
Author(s):  
M. Van Der Klis
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Neutron Stars ◽  
X Ray ◽  
Black Hole Candidate ◽  
Recent Developments ◽  
Low Mass ◽  
Low Magnetic Field ◽  
X Ray Binaries ◽  
Black Hole Candidates

Recent developments in the field of low-mass X-ray binaries are briefly reviewed, with particular emphasis on a comparison between the systems that contain accreting low magnetic-field neutron stars and those that contain black-hole candidates. The possibility that inclination effects play a role in black-hole candidate phenomenology is explored.

scholarly journals High-Mass X-Ray Binaries and OB Runaway Stars

2004 ◽  
Vol 191 ◽  
pp. 128-131 ◽  
Author(s):  
L. Kaper ◽  
A. Van der Meer ◽  
A.H. Tijani
Keyword(s):  
Neutron Stars ◽  
Binary Systems ◽  
Gamma Ray ◽  
Compact Star ◽  
Supernova Explosion ◽  
High Mass ◽  
X Ray ◽  
Fundamental Information ◽  
X Ray Binaries ◽  
Runaway Stars

AbstractHigh-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems and provide fundamental information on the properties of the OB-star primaries and their compact secondaries (neutron star, black hole). Recent observations indicate that the neutron stars in some of these systems (Vela X-1, 4U 1700-37) are more massive than the canonical mass of 1.35 M⊙. These observations have important consequences for the equation of state at supranuclear densities and the formation mechanism(s) of neutron stars and black holes: supernovae and gamma-ray bursts. As a consequence of the supernova explosion that produced the compact star in these systems, HMXBs have high space velocities and thus are runaways. Alternatively, OB-runaway stars can be ejected from a cluster through dynamical interactions. Observations obtained with the Hipparcos satellite indicate that both scenarios are at work.

scholarly journals Search for intermittent X-ray pulsations from neutron stars in low-mass X-ray binaries

2021 ◽  
Vol 38 ◽  
Author(s):  
Yunus Emre Bahar ◽  
Manoneeta Chakraborty ◽  
Ersin Göğüş
Keyword(s):  
Neutron Stars ◽  
Orbital Period ◽  
Oscillation Frequency ◽  
Orbital Motion ◽  
X Rays ◽  
X Ray ◽  
Second Stage ◽  
Corrected Data ◽  
Low Mass ◽  
X Ray Binaries

Abstract We present the results of our extensive binary orbital motion corrected pulsation search for 13 low-mass X-ray binaries. These selected sources exhibit burst oscillations in X-rays with frequencies ranging from 45 to 1 122 Hz and have a binary orbital period varying from 2.1 to 18.9 h. We first determined episodes that contain weak pulsations around the burst oscillation frequency by searching all archival Rossi X-ray Timing Explorer data of these sources. Then, we applied Doppler corrections to these pulsation episodes to discard the smearing effect of the binary orbital motion and searched for recovered pulsations at the second stage. Here we report 75 pulsation episodes that contain weak but coherent pulsations around the burst oscillation frequency. Furthermore, we report eight new episodes that show relatively strong pulsations in the binary orbital motion corrected data.

scholarly journals A Machine Learning Approach For Classifying Low-mass X-ray Binaries Based On Their Compact Object Nature

2020 ◽  
Author(s):  
R Pattnaik ◽  
K Sharma ◽  
K Alabarta ◽  
D Altamirano ◽  
M Chakraborty ◽  
...  
Keyword(s):  
Machine Learning ◽  
Black Hole ◽  
Neutron Star ◽  
Binary Systems ◽  
Compact Object ◽  
X Ray ◽  
Average Accuracy ◽  
Machine Learning Approach ◽  
Low Mass ◽  
X Ray Binaries

Abstract Low Mass X-ray binaries (LMXBs) are binary systems where one of the components is either a black hole or a neutron star and the other is a less massive star. It is challenging to unambiguously determine whether a LMXB hosts a black hole or a neutron star. In the last few decades, multiple observational works have tried, with different levels of success, to address this problem. In this paper, we explore the use of machine learning to tackle this observational challenge. We train a random forest classifier to identify the type of compact object using the energy spectrum in the energy range 5-25 keV obtained from the Rossi X-ray Timing Explorer archive. We report an average accuracy of 87±13% in classifying the spectra of LMXB sources. We further use the trained model for predicting the classes for LMXB systems with unknown or ambiguous classification. With the ever-increasing volume of astronomical data in the X-ray domain from present and upcoming missions (e.g., SWIFT, XMM-Newton, XARM, ATHENA, NICER), such methods can be extremely useful for faster and robust classification of X-ray sources and can also be deployed as part of the data reduction pipeline.

scholarly journals The formation of high-mass black holes in low-mass X-ray binaries

New Astronomy ◽  
1999 ◽  
Vol 4 (4) ◽  
pp. 313-323 ◽  
Author(s):  
G.E. Brown ◽  
C.-H. Lee ◽  
Hans A. Bethe
Keyword(s):  
Black Holes ◽  
High Mass ◽  
X Ray ◽  
Low Mass ◽  
X Ray Binaries

scholarly journals Multiwavelength Modeling the SED of Strongly Interacting Binaries

2011 ◽  
Vol 7 (S282) ◽  
pp. 65-66
Author(s):  
Augustin Skopal
Keyword(s):  
Physical Parameters ◽  
X Rays ◽  
Physical Processes ◽  
Short Contribution ◽  
Composite Spectrum ◽  
X Ray ◽  
Strongly Interacting ◽  
Low Mass ◽  
X Ray Binaries

AbstractThe spectrum of strongly interacting binaries, as for example, high and low mass X-ray binaries, symbiotic (X-ray) binaries and/or classical and recurrent novae, consists of more components of radiation contributing from hard X-rays to radio wavelengths. To understand the basic physical processes responsible for the observed spectrum we have to disentangle the composite spectrum into its individual components, i.e. to determine their physical parameters. In this short contribution I demonstrate the method of modeling the multiwavelength SED on the example of the extragalactic super-soft X-ray source RX J0059.1-7505 (LIN 358).

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