scholarly journals Discovery of Jet-Induced Soft Lags of XTE J1550-564 during Its 1998 Outburst †

Proceedings ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 8
Author(s):  
Arka Chatterjee ◽  
Broja G. Dutta ◽  
Dusmanta Patra ◽  
Sandip K. Chakrabarti ◽  
Prantik Nandi
Keyword(s):  
Accretion Disk ◽  
Time Lag ◽  
Line Of Sight ◽  
Time Lags ◽  
Radio Flux ◽  
X Ray ◽  
Disk Structure ◽  
Timing Properties

X-ray time lags are complicated in nature. The exact reasons for complex lag spectra are as yet unknown. However, the hard lags, in general, are believed to be originated due to inverse Comptonization process. However, the origin of soft lags remained mischievous. Recent studies on “Disk–Jet Connections” revealed that the jets are also contributing in the X-ray spectral and timing properties in a magnitude which was more than what was predicted earlier. In this article, we first show an exact anticorrelation between X-ray time lag and radio flux for XTE J1550-546 during its 1998 outburst. We propose that the soft lags might be generated due to the change in the accretion disk structure along the line of sight during higher jet activity.

scholarly journals Orbital motion and quasi-quantized disk around rotating neutron stars

2014 ◽  
Vol 23 (06) ◽  
pp. 1450053 ◽  
Author(s):  
Joan Jing Wang ◽  
Hsiang-Kuang Chang
Keyword(s):  
Accretion Disk ◽  
Orbital Motion ◽  
Photon Polarization ◽  
X Ray ◽  
Frame Dragging ◽  
Accretion Flows ◽  
Promising Tool ◽  
Disk Structure ◽  
Low Mass ◽  
Inner Region

In accreting neutron star (NS) low-mass X-ray binary (LMXB) systems, NS accretes material from its low-mass companion via a Keplerian disk. In a viscous accretion disk, inflows orbit the NS and spiral in due to dissipative processes, such as the viscous process and collisions of elements. The dynamics of accretion flows in the inner region of an accretion disk is significantly affected by the rotation of NS. The rotation makes NS, thus the spacetime metric, deviate from the originally spherical symmetry, and leads to gravitational quadrupole, on one hand. On the other hand, a rotating NS drags the local inertial frame in its vicinity, which is known as the rotational frame-dragging effect. In this paper, we investigate the orbital motion of accretion flows of accreting NS/LMXBs and demonstrate that the rotational effects of NS result in a band of quasi-quantized structure in the inner region of the accretion disk, which is different, in nature, from the scenario in the strong gravity of black hole arising from the resonance for frequencies related to epicyclic and orbital motions. We also demonstrate that such a disk structure may account for frequencies seen in X-ray variability, such as quasi-periodic oscillations (QPOs), and can be a potential promising tool for the investigation of photon polarization.

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.

Anticorrelated Hard X‐Ray Time Lag in GRS 1915+105: Evidence for a Truncated Accretion Disk

2005 ◽  
Vol 631 (2) ◽  
pp. 1072-1081 ◽  
Author(s):  
Manojendu Choudhury ◽  
A. R. Rao ◽  
Surajit Dasgupta ◽  
J. Pendharkar ◽  
K. Sriram ◽  
...  
Keyword(s):  
Accretion Disk ◽  
Time Lag ◽  
X Ray

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 Inner Disk Structure of Dwarf Novae in the Light of X-Ray Observations

2015 ◽  
Vol 2 (1) ◽  
pp. 116-122 ◽  
Author(s):  
S. Balman
Keyword(s):  
White Dwarf ◽  
Spectral Characteristics ◽  
Time Variability ◽  
Time Lags ◽  
X Rays ◽  
Dwarf Novae ◽  
Disk Radius ◽  
X Ray ◽  
Disk Structure ◽  
Band Limited

Diversity of the X-ray observations of dwarf nova are still not fully understood. I review the X-ray spectral characteristics of dwarf novae during the quiescence in general explained by cooling flow models and the outburst spectra that show hard X-ray emission dominantly with few sources that reveal soft X-ray/EUV blackbody emission. The nature of aperiodic time variability of brightness of dwarf novae shows band limited noise, which can be adequately described in the framework of the model of propagating fluctuations. The frequency of the break (1-6 mHz) indicates inner disk truncation of the optically thick disk with a range of radii (3.0-10.0)×109 cm. The RXTE and optical (RTT150) data of SS Cyg in outburst and quiescence reveal that the inner disk radius moves towards the white dwarf and receeds as the outburst declines to quiescence. A preliminary analysis of SU UMa indicates a similar behaviour. In addition, I find that the outburst spectra of WZ Sge shows two component spectrum of only hard X-ray emission, one of which may be fitted with a power law suggesting thermal Comptonization occuring in the system. Cross-correlations between the simultaneous UV and X-ray light curves (XMM −Newton) of five DNe in quiescence show time lags in the X-rays of 96-181 sec consistent with travel time of matter from a truncated inner disk to the white dwarf surface. All this suggests that dwarf novae and other plausible nonmagnetic systems have truncated accretion disks indicating that the disks may be partially evaporated and the accretion may occur through hot (coronal) flows in the disk.

scholarly journals An X-Ray Microlensing Test of AU-Scale Accretion Disk Structure in Q2237+0305

1998 ◽  
Vol 501 (1) ◽  
pp. L41-L44 ◽  
Author(s):  
Atsunori Yonehara ◽  
Shin Mineshige ◽  
Tadahiro Manmoto ◽  
Jun Fukue ◽  
Masayuki Umemura ◽  
...  
Keyword(s):  
Accretion Disk ◽  
X Ray ◽  
Disk Structure

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.

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