JET MODELS FOR NEUTRON STAR X-RAY BINARIES

2012 ◽  
Vol 08 ◽  
pp. 108-113 ◽  
Author(s):  
SIMONE MIGLIARI ◽  
GABRIELE GHISELLINI ◽  
JAMES MILLER-JONES ◽  
DAVID RUSSELL
Keyword(s):  
Neutron Star ◽  
Compact Object ◽  
Young Stellar Objects ◽  
Jet Formation ◽  
Stellar Objects ◽  
X Ray ◽  
The Status ◽  
Observational Knowledge ◽  
X Ray Binaries

A variety of different models for jet formation have been developed over the years (mainly) for black hole systems and young stellar objects. Conclusive observational constraints which would favor one particular mechanism are difficult to obtain. Neutron star X-ray binaries are crucial for advancing our understanding of jet formation in general, building a bridge between the two most studied jet-producing classes of systems: black holes, i.e. non-magnetized, relativistic objects, and young stellar objects, i.e. non-relativistic, magnetized stars. I will briefly review the status of our observational knowledge of jets in neutron star X-ray binaries, with a focus on the parameters which might be involved in the production of jets. I will present recent works and current observational programs aiming to quantify the role of the compact object in the formation of jets in neutron star systems. Finally, I will test a jet model developed for young stellar objects, the X–wind model, on a neutron star system.

scholarly journals Jets from neutron star X-ray binaries: towards a unified scheme

2010 ◽  
Vol 6 (S275) ◽  
pp. 233-241
Author(s):  
Simone Migliari
Keyword(s):  
Magnetic Field ◽  
Black Holes ◽  
Neutron Star ◽  
Accretion Rate ◽  
X Ray ◽  
Multi Wavelength ◽  
Observational Knowledge ◽  
Low Magnetic Field ◽  
X Ray Binaries

AbstractSystematic multi-wavelength studies of neutron stars (NSs) have shown a jet and disk-jet coupling phenomenology which resembles, although with some important differences, that observed in black holes; ultra-relativistic transient ejection, steady compact jets, accretion-ejection cycles are indeed observed in NSs. I will review our observational knowledge of jet in NS X-ray binaries, focusing on the role of the parameters of the system which might be involved in the production of jets. First, I will discuss the role of the accretion rate, presenting a unified scheme for accretion-jet production throughout the different sub-classes of low-magnetic field NSs. Then, I will attempt to (make the first steps to) quantify the role of spin and magnetic field in powering the jet.

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 Anisotropic neutron stars by gravitational decoupling

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
V. A. Torres-Sánchez ◽  
E. Contreras
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Perfect Fluid ◽  
Compact Object ◽  
Adiabatic Index ◽  
X Ray ◽  
Binary Pulsar ◽  
Stable Solutions ◽  
X Ray Binaries ◽  
Fluid Configuration

Abstract In this work we obtain an anisotropic neutron star solution by gravitational decoupling starting from a perfect fluid configuration which has been used to model the compact object PSR J0348+0432. Additionally, we consider the same solution to model the Binary Pulsar SAX J1808.4-3658 and X-ray Binaries Her X-1 and Cen X-3 ones. We study the acceptability conditions and obtain that the MGD-deformed solution obey the same physical requirements as its isotropic counterpart. Finally, we conclude that the most stable solutions, according to the adiabatic index and gravitational cracking criterion, are those with the smallest compactness parameters, namely SAX J1808.4-3658 and Her X-1.

Do neutron stars produce jets?

1986 ◽  
Vol 64 (4) ◽  
pp. 474-478 ◽  
Author(s):  
Eric D. Feigelson
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Binary Systems ◽  
Crab Nebula ◽  
Compact Object ◽  
Radio Pulsars ◽  
X Ray ◽  
The Crab Nebula ◽  
X Ray Binaries

The evidence for jets emanating from neutron stars is reviewed. Isolated radio pulsars do not appear to produce collimated outflows. A few supernova remnants, notably the Crab nebula, exhibit jetlike protrusions at their outer boundaries. These are probably "blowouts" of the plasma in the remnant rather than true jets from a neutron star. However, several cases of degenerate stars in X-ray binary systems do make jets. SS433 has twin precessing jets moving outward at v ~ 0.26c, and Sco X-1 has radio lobes with v ~ 0.0001c. Cyg X-3 appears to eject synchrotron plasmoids at high velocities. Other X-ray binaries associated with variable radio sources are discussed; some are interesting candidates for collimated outflow. G109.1-1.0 is an X-ray binary in a supernova remnant that may have radio or X-ray jets. It is not clear in all these cases, however, that the compact object is a neutron star and not a black hole or white dwarf.A tentative conclusion is reached that isolated neutron stars do not produce jets, but degenerate stars in accreting binary systems can. This suggests that the presence of an accretion disk, rather than the characteristics of an isolated pulsar's dipole magnetosphere, is critical in making collimated outflows.

scholarly journals Measuring the Masses of Compact Objects in Low-Mass X-Ray Binaries

2004 ◽  
Vol 194 ◽  
pp. 214-214
Author(s):  
Dawn M. Gelino
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Compact Object ◽  
Compact Objects ◽  
Orbital Inclination ◽  
X Ray ◽  
Secondary Star ◽  
Low Mass ◽  
The Masses ◽  
X Ray Binaries

Low-mass X-ray binaries (LMXBs) contain compact, black hole (BH) or neutron star (NS) primaries, and cool, low-mass secondary stars. We measure the orbital inclination of the system in quiescence by modeling infrared (IR) ellipsoidal variations from the secondary star in order to determine the compact object mass. I present our results for a few LMXBs, including the first BH that appears to conclusively fall in the 3-5 M⊙ range.

scholarly journals High-frequency quasi-periodic oscillations in accreting neutron-star systems

2009 ◽  
Vol 5 (H15) ◽  
pp. 116-120
Author(s):  
Mariano Méndez
Keyword(s):  
Neutron Star ◽  
High Frequency ◽  
Periodic Oscillations ◽  
X Ray ◽  
X Ray Binaries

AbstractKilohertz quasi-periodic oscillations (kHz QPOs) are the fastest (almost coherent) variability measured in accreting X-ray binaries with a neutron-star primary. Here I review the rôle of the neutron-star spin in driving the frequencies of the kHz QPOs.

scholarly journals Investigating accretion disk – radio jet coupling across the stellar mass scale

2010 ◽  
Vol 6 (S275) ◽  
pp. 224-232
Author(s):  
James C. A. Miller-Jones ◽  
Gregory R. Sivakoff ◽  
Diego Altamirano ◽  
Elmar G. Körding ◽  
Hans A. Krimm ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
White Dwarf ◽  
Angular Resolution ◽  
Stellar Mass ◽  
Mass Scale ◽  
High Angular Resolution ◽  
Jet Formation ◽  
X Ray ◽  
X Ray Binaries

AbstractRelationships between the X-ray and radio behavior of black hole X-ray binaries during outbursts have established a fundamental coupling between the accretion disks and radio jets in these systems. I begin by reviewing the prevailing paradigm for this disk-jet coupling, also highlighting what we know about similarities and differences with neutron star and white dwarf binaries. Until recently, this paradigm had not been directly tested with dedicated high-angular resolution radio imaging over entire outbursts. Moreover, such high-resolution monitoring campaigns had not previously targetted outbursts in which the compact object was either a neutron star or a white dwarf. To address this issue, we have embarked on the Jet Acceleration and Collimation Probe Of Transient X-Ray Binaries (JACPOT XRB) project, which aims to use high angular resolution observations to compare disk-jet coupling across the stellar mass scale, with the goal of probing the importance of the depth of the gravitational potential well, the stellar surface and the stellar magnetic field, on jet formation. Our team has recently concluded its first monitoring series, including (E)VLA, VLBA, X-ray, optical, and near-infrared observations of entire outbursts of the black hole candidate H 1743-322, the neutron star system Aquila X-1, and the white dwarf system SS Cyg. Here I present preliminary results from this work, largely confirming the current paradigm, but highlighting some intriguing new behavior, and suggesting a possible difference in the jet formation process between neutron star and black hole systems.

The Formation of Astrophysical Jets

1997 ◽  
Vol 163 ◽  
pp. 845-866 ◽  
Author(s):  
Mario Livio
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Young Stellar Objects ◽  
Astrophysical Jets ◽  
Stellar Objects ◽  
X Ray ◽  
Astrophysical Objects ◽  
Low Mass ◽  
Wind Source ◽  
X Ray Binaries

AbstractIt is assumed that the acceleration and collimation mechanisms of jets are the same in all the classes of astrophysical objects which are observed to produce jets. These classes now include: active galactic nuclei, young stellar objects, massive x-ray binaries, low mass x-ray binaries, black hole x-ray transients, symbiotic systems, planetary nebulae, and supersoft x-ray sources.On the basis of this assumption, an attempt is made, to identify the necessary ingredients for the acceleration and collimation mechanism. It is argued that: (i) jets are produced at the center of accretion disks which are threaded by a vertical magnetic field, (ii) the production of powerful jets requires, in addition, an energy/wind source associated with the central object. Tentative explanations for the presence of jets in some classes of objects and absence in others are given. Some critical observation that can test the ideas presented in this paper are suggested.

On the nature of the X-ray outbursts in Be/X-ray binaries

2018 ◽  
Vol 14 (S346) ◽  
pp. 146-148
Author(s):  
Jingzhi Yan ◽  
Wei Liu ◽  
Peng Zhang ◽  
Qingzhong Liu
Keyword(s):  
Neutron Star ◽  
Compact Object ◽  
Optical Emission ◽  
Light Curves ◽  
High Mass ◽  
Circumstellar Disk ◽  
X Ray ◽  
Be Star ◽  
The Relationship ◽  
X Ray Binaries

AbstractBe/X-ray binaries are a major subclass of high mass X-ray binaries. Two different X-ray outbursts are displayed in the X-ray light curves of such systems. It is generally believed that the X-ray outbursts are connected with the neutron star periastron passage of the circumstellar disk around the Be star. The optical emission of the Be star should be very important to understand the X-ray emission of the compact object. We have monitored several Be/X-ray binaries photometrically and spectroscopically in the optical band. The relationship between the optical emission and X-ray activity is described, which is very useful to explain the X-ray outbursts in Be/X-ray binaries.

scholarly journals IGR J17329-2731: The birth of a symbiotic X-ray binary

2018 ◽  
Vol 613 ◽  
pp. A22 ◽  
Author(s):  
E. Bozzo ◽  
A. Bahramian ◽  
C. Ferrigno ◽  
A. Sanna ◽  
J. Strader ◽  
...  
Keyword(s):  
Neutron Star ◽  
Compact Object ◽  
Light Curves ◽  
Strong Absorption ◽  
Emission Lines ◽  
Optical Data ◽  
X Rays ◽  
X Ray ◽  
The Past ◽  
X Ray Binaries

We report on the results of the multiwavelength campaign carried out after the discovery of the INTEGRAL transient IGR J17329-2731. The optical data collected with the SOAR telescope allowed us to identify the donor star in this system as a late M giant at a distance of 2.7-1.2+3.4 kpc. The data collected quasi-simultaneously with XMM–Newton and NuSTAR showed the presence of a modulation with a period of 6680 ± 3 s in the X-ray light curves of the source. This unveils that the compact object hosted in this system is a slowly rotating neutron star. The broadband X-ray spectrum showed the presence of a strong absorption (≫1023 cm−2) and prominent emission lines at 6.4 keV, and 7.1 keV. These features are usually found in wind-fed systems, in which the emission lines result from the fluorescence of the X-rays from the accreting compact object on the surrounding stellar wind. The presence of a strong absorption line around ~21 keV in the spectrum suggests a cyclotron origin, thus allowing us to estimate the neutron star magnetic field as ~2.4 × 1012 G. All evidencethus suggests IGR J17329-2731 is a symbiotic X-ray binary. As no X-ray emission was ever observed from the location of IGR J17329-2731 by INTEGRAL (or other X-ray facilities) during the past 15 yr in orbit and considering that symbiotic X-ray binaries are known to be variable but persistent X-ray sources, we concluded that INTEGRAL caught the first detectable X-ray emission from IGR J17329-2731 when the source shined as a symbiotic X-ray binary. The Swift XRT monitoring performed up to ~3 months after the discovery of the source, showed that it maintained a relatively stable X-ray flux and spectral properties.

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