scholarly journals Time-domain variability properties of XTE J1650−500 during its 2001 outburst: evidence of disc–jet connection

2020 ◽  
Vol 497 (4) ◽  
pp. 4222-4230
Author(s):  
Arka Chatterjee ◽  
Broja G Dutta ◽  
Prantik Nandi ◽  
Sandip K Chakrabarti
Keyword(s):  
Black Hole ◽  
Time Lag ◽  
Periodic Oscillation ◽  
Time Lags ◽  
Central Black Hole ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Transient Sources ◽  
Unique Nature ◽  
Hard State

ABSTRACT The evolution of variability properties of Galactic transient sources is a diagnostic tool to understand various regimes of the accretion flow and its dynamics close to the central black hole. In this paper, we concentrate on the variability properties of the X-ray transient XTE J1650−500 and investigate the evolution of viscous delay, time lag, quasi-periodic oscillation (QPO) frequency, and their energy dependence throughout the rising phase as observed by Rossi X-ray Timing Explorer(RXTE) during its outburst in 2001. Our analysis reveals (1) a delay of 12 ± 1 d between 1 d-averaged hard (5–12 keV) and soft (1.5–3 keV) photon light curves as observed by RXTE/ASM; (2) QPOs with high rms values are observed in lower energy (4–8 keV) range; (3) the QPO frequencies and associated time lags were anticorrelated during the initial days of the rising phase, and later on, they were found to be correlated; (4) the time lags of Fe-line photons with respect to hard and soft photons remained almost constant during the initial days of hard state and the lag magnitude increased during the state transition. We perform comparative studies with outbursts of GX 339−4 and XTE J1550−564. We find the evolution of time lags associated with the QPO characteristics during the outburst – stronger QPOs at low energy and constant lags of broad Fe-line photons present a unique nature of outburst profile in XTE J1650−500. The possible cause of such variabilities is explained by considering disc–jet geometry closer to the central black hole.

scholarly journals Long-term variability of Swift J1753.5−0127: X-ray spectral–temporal correlations during state transitions

2019 ◽  
Vol 487 (1) ◽  
pp. 1439-1446
Author(s):  
Qingcui Bu ◽  
Lian Tao ◽  
Yu Lu ◽  
Shuangnan Zhang ◽  
Liang Zhang ◽  
...  
Keyword(s):  
Black Hole ◽  
Intermediate State ◽  
State Transition ◽  
Time Lag ◽  
Periodic Oscillation ◽  
State Transitions ◽  
Time Lags ◽  
X Ray ◽  
Hard State

ABSTRACT We studied the long-term evolution of the spectral–temporal correlated properties of the black hole candidate Swift J1753.5−0127 from the onset of its outburst until 2011 with the Rossi X-ray Timing Explorer (RXTE). The source stayed most of its lifetime during hard state, with occasionally transitioned to the hard intermediate state. Similar to typical black hole transients, Swift J1753.5−0127 traces a clear hard line in absolute rms–intensity diagram during the low hard state, with expected highest absolute rms, while shows a clear turn during the hard intermediate state, accompanied by lower absolute rms. Different from Cyg X-1, we found that frequency-dependent time lag increased significantly in the 0.02–3.2 Hz band during state transition in this source. The X-ray time lags in 0.02–3.2 Hz can therefore be used as indicators of state transition in this source. Type-C quasi-periodic oscillation frequency is positively related with its fractional rms and X-ray photon index, suggesting a moving inwards disc/corona scenario. We discussed the physical interpretation of our results in this paper.

scholarly journals Energy and time-lag spectra of galactic black-hole X-ray sources in the low/hard state

2003 ◽  
Vol 403 (1) ◽  
pp. L15-L18 ◽  
Author(s):  
P. Reig ◽  
N. D. Kylafis ◽  
D. Giannios
Keyword(s):  
Black Hole ◽  
Time Lag ◽  
X Ray ◽  
Galactic Black Hole ◽  
Hard State

scholarly journals Time lags between starburst and AGN activity in galaxy mergers

2013 ◽  
Vol 9 (S303) ◽  
pp. 379-381
Author(s):  
M. Blank ◽  
W. J. Duschl
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Velocity Dispersion ◽  
Time Lag ◽  
Time Lags ◽  
Galaxy Mergers ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Stellar Velocity ◽  
Flow Through

AbstractWe show that the observed time lag between starburst and AGN activity can be explained by a viscous time lag the gas needs to flow through the AGN's accretion disk before reaching the central black hole. Our calculations reproduce the observed time lag and are in agreement with the observed correlation between black hole mass and stellar velocity dispersion.

scholarly journals Inclination effects on the X-ray emission of Galactic black-hole binaries

2019 ◽  
Vol 625 ◽  
pp. A90 ◽  
Author(s):  
Pablo Reig ◽  
Nikolaos D. Kylafis
Keyword(s):  
Black Hole ◽  
Linear Regression Analysis ◽  
Time Lag ◽  
Light Curves ◽  
Energy Spectra ◽  
Time Lags ◽  
X Ray ◽  
Galactic Black Hole ◽  
Photon Index ◽  
Inclination Angles

Context. Galactic black-hole X-ray binaries (BHBs) emit a compact, optically thick, mildly relativistic radio jet when they are in hard and hard-intermediate states. In these states, BHBs exhibit a correlation between the time lag of hard with respect to softer photons and the photon index of the power law component that characterizes the X-ray spectral continuum above ∼10 keV. The correlation, however, shows large scatter. In recent years, several works have brought to light the importance of taking into account the inclination of the systems to understand the X-ray and radio phenomenology of BHBs. Aims. Our objective is to investigate the role that the inclination plays on the correlation between the time lag and photon index. Methods. We obtained RXTE energy spectra and light curves of a sample of BHBs with different inclination angles. We computed the photon index and the time lag between hard and soft photons and performed a correlation and linear regression analysis of the two variables. We also computed energy spectra and light curves of BHBs using the Monte Carlo technique that reproduces the process of Comptonization in the jet. We account for the inclination effects by recording the photons that escape from the jet at different angles. From the simulated light curves and spectra we obtained model-dependent photon index and time lags, which we compared with those obtained from the real data. Results. We find that the correlation between the time lag and photon index is tight in low-inclination systems and becomes weaker in high-inclination systems. The amplitude of the lags is also larger at low- and intermediate-inclination angles than at high inclination. We also find that the photon index and time lag, obtained from the simulated spectra and light curves, also follow different relationships for different inclination angle ranges. Our jet model reproduces the observations remarkably well. The same set of models that reproduces the correlation for the low-inclination systems, also accounts for the correlation for intermediate- and high-inclination systems fairly well. Conclusions. The large dispersion observed in the time lag – photon index correlation in BHBs can naturally be explained as an inclination effect. Comptonization in the jet explains the steeper dependence of the lags on the photon index in low- and intermediate-inclination systems than in high-inclination systems.

scholarly journals A Possible Quasi-Periodic Oscillation in the X-ray Emission of 3C 120

Galaxies ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 20
Author(s):  
Aditi Agarwal ◽  
Priyanka Rani ◽  
Raj Prince ◽  
C. S. Stalin ◽  
G. C. Anupama ◽  
...  
Keyword(s):  
Black Hole ◽  
Kerr Black Hole ◽  
Periodic Oscillation ◽  
Black Hole Mass ◽  
Telescope Array ◽  
Quasi Periodic Oscillation ◽  
X Ray ◽  
Reverberation Mapping ◽  
Power Spectral ◽  
3C 120

We present here the detection of a possible quasi-periodic oscillation (QPO) signal in the X-ray light curve of the active galactic nucleus 3C 120, a broad line radio galaxy at z = 0.033. The hint of a QPO at the 3σ level at 7.1 × 10−6 Hz (∼1.65 days) was detected based on the analysis of X-ray data acquired in the 3–79 keV band by the Nuclear Spectroscopic Telescope Array (NuSTAR). The data, when processed separately in the soft (3–10 keV), hard (10–79 keV) and the total (3–79 keV) bands using four different techniques, namely discrete correlation function, Lomb Scargle periodogram, structure–function, and power spectral density indicated the presence of a QPO. 3C 120 very well fits in the negative correlation in the frequency of the QPO versus the black hole mass (FQPO versus MBH) diagram known for stellar-mass and supermassive black hole sources. Considering the observed signs of QPO to represent the innermost stable orbit of the accretion disk, we found a black hole mass of 1.9×109 M⊙ for a Kerr black hole and 3.04×108 M⊙ for a Schwarzschild black hole. This deduced black hole mass from QPO measurement is a few times larger than the black hole mass obtained from reverberation mapping observations.

scholarly journals A giant X-ray dust scattering ring discovered with SRG/eROSITA around the black hole transient MAXI J1348–630

2021 ◽  
Vol 647 ◽  
pp. A7
Author(s):  
G. Lamer ◽  
A. D. Schwope ◽  
P. Predehl ◽  
I. Traulsen ◽  
J. Wilms ◽  
...  
Keyword(s):  
Black Hole ◽  
Outer Diameter ◽  
Time Lags ◽  
Distance Measurements ◽  
X Ray ◽  
Bolometric Luminosity ◽  
Sky Survey ◽  
Transient Sources ◽  
Measured Time ◽  
Mass Estimate

We report the discovery of a giant dust scattering ring around the Black Hole transient MAXI J1348−630 with SRG/eROSITA during its first X-ray all-sky survey. During the discovery observation in February 2020, the ring had an outer diameter of 1.3 deg, growing to 1.6 deg by the time of the second all-sky survey scan in August 2020. This makes the new dust ring by far the largest X-ray scattering ring observed so far. Dust scattering halos, in particular the rings found around transient sources, provide an opportunity to make precise distance measurements towards the original X-ray sources. We combine data from SRG/eROSITA, XMM-Newton, MAXI, and Gaia to measure the geometrical distance of MAXI J1348−630. The Gaia data place the scattering dust at a distance of 2050 pc. Based on the measured time lags and the geometry of the ring we find MAXI J1348−630 at a distance of 3390 pc with a statistical uncertainty of only 1.1% and a systematic uncertainty of 10% caused mainly by the parallax offset of Gaia. This result makes MAXI J1348−630 one of the black hole transients with the most accurately determined distances. The new distance leads to a revised mass estimate for the black hole of 11 ± 2 M⊙. The transition to the soft state during the outburst occurred when the bolometric luminosity of MAXI J1348−630 reached 1.7% of its Eddington luminosity.

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 Correlation of time lag and photon index in GX 339-4

2018 ◽  
Vol 614 ◽  
pp. L5 ◽  
Author(s):  
Nikolaos D. Kylafis ◽  
Pablo Reig
Keyword(s):  
Black Hole ◽  
Power Law ◽  
Time Lag ◽  
Radio Spectrum ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Photon Index ◽  
Hard State ◽  
Two Parameters ◽  
Soft Disk

Context. Black hole transients, as a class, exhibit during their outbursts a correlation between the time lag of hard photons with respect to softer ones and the photon index of the hard X-ray power law. The correlation is not very tight and therefore it is necessary to examine it source by source. Aims. The objective of the present work is to investigate in detail the correlation between the time lag and the photon index in GX 339-4, which is the best studied black hole transient. Methods. We have obtained RXTE energy spectra and light curves and have computed the photon index and the time lag of the 9–15 keV photons with respect to the 2–6 keV photons. The observations cover the first stages of the hard state, the pure hard state, and the hard-intermediate state. Results. We have found a tight correlation between time lag and photon index Γ in the hard and hard-intermediate states. At low Γ, the correlation is positive; it becomes negative at high Γ By assuming that the hard X-ray power-law index Γ is produced by inverse Compton scattering of soft disk photons in the jet, we have reproduced the entire correlation by varying two parameters in the jet: the radius of the jet at its base R0 and the Thomson optical depth along the jet τ∥. We have found that as the luminosity of the source increases, R0 initially increases and then decreases. This behavior is expected in the context of the Cosmic Battery. Conclusions. Our jet model nicely explains the correlation with reasonable values of the parameters R0 and τ∥ These parameters also correlate between themselves. As a further test of our model, we predict the break frequency in the radio spectrum as a function of the photon index during the rising part of an outburst.

scholarly journals MAXI J1820+070 with NuSTAR I. An increase in variability frequency but a stable reflection spectrum: coronal properties and implications for the inner disc in black hole binaries

2019 ◽  
Vol 490 (1) ◽  
pp. 1350-1362 ◽  
Author(s):  
D J K Buisson ◽  
A C Fabian ◽  
D Barret ◽  
F Fürst ◽  
P Gandhi ◽  
...  
Keyword(s):  
Black Hole ◽  
Low Frequency ◽  
Periodic Oscillation ◽  
Thermal Electron ◽  
X Ray ◽  
Black Hole Binaries ◽  
Black Hole Candidate ◽  
Long Duration ◽  
Hard State ◽  
Characteristic Features

ABSTRACT MAXI J1820+070 (optical counterpart ASASSN-18ey) is a black hole candidate discovered through its recent very bright outburst. The low extinction column and long duration at high flux allow detailed measurements of the accretion process to be made. In this work, we compare the evolution of X-ray spectral and timing properties through the initial hard state of the outburst. We show that the inner accretion disc, as measured by relativistic reflection, remains steady throughout this period of the outburst. Nevertheless, subtle spectral variability is observed, which is well explained by a change in coronal geometry. However, characteristic features of the temporal variability – low-frequency roll-over and quasi-periodic oscillation frequency – increase drastically in frequency, as the outburst proceeds. This suggests that the variability time-scales are governed by coronal conditions rather than solely by the inner disc radius. We also find a strong correlation between X-ray luminosity and coronal temperature. This can be explained by electron pair production with a changing effective radius and a non-thermal electron fraction of $\sim 20$ per cent.

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