scholarly journals How to Distinguish Neutron Star and Black Hole X‐Ray Binaries? Spectral Index and Quasi‐Periodic Oscillation Frequency Correlation

2005 ◽  
Vol 626 (1) ◽  
pp. 298-306 ◽  
Author(s):  
Lev Titarchuk ◽  
Nickolai Shaposhnikov
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Spectral Index ◽  
Oscillation Frequency ◽  
Periodic Oscillation ◽  
Quasi Periodic Oscillation ◽  
Frequency Correlation ◽  
X Ray ◽  
X Ray Binaries

scholarly journals A global study of type B quasi-periodic oscillation in black hole X-ray binaries

2016 ◽  
Vol 466 (1) ◽  
pp. 564-573 ◽  
Author(s):  
H. Q. Gao ◽  
Liang Zhang ◽  
Yupeng Chen ◽  
Zhen Zhang ◽  
Li Chen ◽  
...  
Keyword(s):  
Black Hole ◽  
Periodic Oscillation ◽  
Type B ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Global Study ◽  
X Ray Binaries

scholarly journals Millisecond Time Variations of X-Ray Binaries

1998 ◽  
Vol 188 ◽  
pp. 107-110
Author(s):  
J. H. Swank
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Beat Frequency ◽  
Rotation Period ◽  
Periodic Oscillation ◽  
Frequency Model ◽  
X Ray ◽  
Low Mass ◽  
The Difference ◽  
X Ray Binaries

Millisecond time-scales are natural for some neutron star and black hole processes, although possibly difficult to observe. The Rossi X-Ray Timing Explorer (RXTE) has found that for the neutron stars in low-mass X-ray binaries (LMXB) there are flux oscillations at high frequencies, with large amplitudes. Z sources and bursters tend to exhibit oscillations in the range 300-1200 Hz. Persistent emission may exhibit one or both of two features. In bursts from different bursters, a nearly coherent pulsation is seen, which may be the rotation period of the neutron star. For some the frequency equals the difference between the two higher frequencies, suggesting a beat frequency model, but in others it is twice the difference. The sources span two orders of magnitude in accretion rate, yet the properties are similar. The similar maximum frequencies suggests that it corresponds to the Kepler orbit frequency at the minimum stable orbit or the neutron star surface, either of which would determine the neutron star masses, radii and equation of state. Theories of accretion onto black holes predict a quasi-periodic oscillation (QPO) related to the inner accretion disk. The two microquasar black hole candidates (BHCs) have exhibited candidates for this or related frequencies.

scholarly journals A minimal timescale for the continuum in 4U 1608-52 and Aql X-1

2021 ◽  
Vol 502 (1) ◽  
pp. L72-L78
Author(s):  
K Mohamed ◽  
E Sonbas ◽  
K S Dhuga ◽  
E Göğüş ◽  
A Tuncer ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Power Spectra ◽  
Light Curves ◽  
State Transitions ◽  
Strong Positive Correlation ◽  
Present Evidence ◽  
X Ray ◽  
X Ray Binaries ◽  
The Continuum

ABSTRACT Similar to black hole X-ray binary transients, hysteresis-like state transitions are also seen in some neutron-star X-ray binaries. Using a method based on wavelets and light curves constructed from archival Rossi X-ray Timing Explorer observations, we extract a minimal timescale over the complete range of transitions for 4U 1608-52 during the 2002 and 2007 outbursts and the 1999 and 2000 outbursts for Aql X-1. We present evidence for a strong positive correlation between this minimal timescale and a similar timescale extracted from the corresponding power spectra of these sources.

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 Radio Emitting X-Ray Binary Stars

1996 ◽  
Vol 158 ◽  
pp. 371-374
Author(s):  
R. E. Spencer
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Radio Emission ◽  
Binary Stars ◽  
X Ray ◽  
Ss 433 ◽  
Normal Star ◽  
Large Numbers ◽  
X Ray Binaries

Some of the most astrophysically interesting objects are found among the radio-emitting X-ray binary stars (REXRB). The class includes the well-studied objects such as SS 433, Cyg X-3 and Sco X-1. The recent discoveries of relativistic ejection of radio knots in the X-ray transients 1915+105 (Mirabel & Rodriguez 1994) and 1655–40 (Hjellming & Rupen 1995) well illustrate the extreme nature of some of these objects.X-ray binaries are semi-detached binary stars in which matter is transfered from a more or less normal star onto a neutron star or black hole. X-ray satellites have detected large numbers of these objects (193 in a recent catalogue by van Paradijs 1995). However only a small fraction of these are known to have radio emission (e.g. Hjellming 1988).

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