scholarly journals High‐ and Low‐Frequency Quasi‐periodic Oscillations in the X‐Ray Light Curves of the Black Hole Transient H1743−322

2005 ◽  
Vol 623 (1) ◽  
pp. 383-391 ◽  
Author(s):  
Jeroen Homan ◽  
Jon M. Miller ◽  
Rudy Wijnands ◽  
Michiel van der Klis ◽  
Tomaso Belloni ◽  
...  
Keyword(s):  
Black Hole ◽  
Low Frequency ◽  
Light Curves ◽  
Periodic Oscillations ◽  
X Ray

scholarly journals A non-linear mathematical model for the X-ray variability classes of the microquasar GRS 1915+105 – I. Quiescent, spiking states, and quasi-periodic oscillations

2020 ◽  
Vol 495 (1) ◽  
pp. 1110-1121 ◽  
Author(s):  
E Massaro ◽  
F Capitanio ◽  
M Feroci ◽  
T Mineo ◽  
A Ardito ◽  
...  
Keyword(s):  
Differential Equations ◽  
Equilibrium Points ◽  
Low Frequency ◽  
Input Function ◽  
Light Curves ◽  
Stable Region ◽  
Periodic Oscillations ◽  
X Ray ◽  
Unstable Solutions ◽  
Unified View

ABSTRACT The microquasar GRS 1915+105 is known to exhibit a very variable X-ray emission on different time-scales and patterns. We propose a system of two ordinary differential equations, adapted from the Hindmarsh–Rose model, with two dynamical variables x(t), y(t), and an input constant parameter J0, to which we added a random white noise, whose solutions for the x(t) variable reproduce consistently the X-ray light curves of several variability classes as well as the development of low-frequency quasi-periodic oscillations (QPO). We show that changing only the value of J0, the system moves from stable to unstable solutions and the resulting light curves reproduce those of the quiescent classes like ϕ and χ, the δ class and the spiking ρ class. Moreover, we found that increasing the values of J0 the system induces high-frequency oscillations that evolve into QPO when it moves into another stable region. This system of differential equations gives then a unified view of the variability of GRS 1915+105 in term of transitions between stable and unstable states driven by a single input function J0. We also present the results of a stability analysis of the equilibrium points and some considerations on the existence of periodic solutions.

scholarly journals A model of low-frequency quasi-periodic oscillations in black hole X-ray binaries

2012 ◽  
Vol 12 (6) ◽  
pp. 661-670 ◽  
Author(s):  
Zhi-Yun Wang ◽  
Chang-Yin Huang ◽  
Ding-Xiong Wang ◽  
Jiu-Zhou Wang
Keyword(s):  
Black Hole ◽  
Low Frequency ◽  
Periodic Oscillations ◽  
X Ray ◽  
X Ray Binaries

scholarly journals On the frequency correlations of low-frequency QPOs with kilohertz QPOs in accreting millisecond X-ray pulsars

2019 ◽  
Vol 490 (4) ◽  
pp. 5270-5284 ◽  
Author(s):  
Marieke van Doesburgh ◽  
Michiel van der Klis
Keyword(s):  
Black Hole ◽  
Power Law ◽  
Equations Of State ◽  
Low Frequency ◽  
Data Sets ◽  
Periodic Oscillations ◽  
X Ray ◽  
Frame Dragging ◽  
Low Mass ◽  
X Ray Binaries

ABSTRACT We investigate frequency correlations of low frequency (LF, <80 Hz) and kHz quasi-periodic oscillations (QPOs) using the complete RXTE data sets on six accreting millisecond X-ray pulsars (AMXPs) and compare them to those of non-pulsating neutron star (NS) low-mass X-ray binaries with known spin. For the AMXPs SAX J1808.4−3658 and XTE J1807−294, we find frequency-correlation power-law indices that, surprisingly, are significantly lower than in the non-pulsars, and consistent with the relativistic precession model (RPM) prediction of 2.0 appropriate to test-particle orbital and Lense–Thirring precession frequencies. As previously reported, power-law normalizations are significantly higher in these AMXPs than in the non-pulsating sources, leading to requirements on the NS specific moment of inertia in this model that cannot be satisfied with realistic equations of state. At least two other AMXPs show frequency correlations inconsistent with those of SAX J1808.4−3658 and XTE J1807−294, and possibly similar to those of the non-pulsating sources; for two AMXPs no conclusions could be drawn. We discuss these results in the context of a model that has had success in black hole (BH) systems involving a torus-like hot inner flow precessing due to (prograde) frame dragging, and a scenario in which additional (retrograde) magnetic and classical precession torques not present in BH systems are also considered. We show that a combination of these interpretations may accommodate our results.

scholarly journals Properties of Faint X-ray Activity of XTE J1908+094 in 2019

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 25
Author(s):  
Debjit Chatterjee ◽  
Arghajit Jana ◽  
Kaushik Chatterjee ◽  
Riya Bhowmick ◽  
Sujoy Kumar Nath ◽  
...  
Keyword(s):  
Black Hole ◽  
Temporal Analysis ◽  
Power Density Spectrum ◽  
Periodic Oscillations ◽  
Telescope Array ◽  
Density Spectrum ◽  
X Ray ◽  
Black Hole Candidate ◽  
Short Period ◽  
Spectral State

We study the properties of the faint X-ray activity of Galactic transient black hole candidate XTE J1908+094 during its 2019 outburst. Here, we report the results of detailed spectral and temporal analysis during this outburst using observations from Nuclear Spectroscopic Telescope Array (NuSTAR). We have not observed any quasi-periodic-oscillations (QPOs) in the power density spectrum (PDS). The spectral study suggests that the source remained in the softer (more precisely, in the soft–intermediate) spectral state during this short period of X-ray activity. We notice a faint but broad Fe Kα emission line at around 6.5 keV. We also estimate the probable mass of the black hole to be 6.5−0.7+0.5M⊙, with 90% confidence.

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.

Low frequency quasi-periodic oscillations in the hard X-ray emission from Cygnus X-1

2000 ◽  
Vol 25 (3-4) ◽  
pp. 429-432
Author(s):  
B. Paul ◽  
P.C. Agrawal ◽  
A.R. Rao
Keyword(s):  
Low Frequency ◽  
Periodic Oscillations ◽  
X Ray
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