scholarly journals Comptonisation and Time-lags in Multi-temperature Plasmas Surrounding Compact Objects

2000 ◽  
Vol 17 (1) ◽  
pp. 48-55
Author(s):  
Jason Cullen
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Time Lag ◽  
Compact Objects ◽  
Time Lags ◽  
Monte Carlo Code ◽  
Energy Bands ◽  
Temporal Behaviour ◽  
Galactic Black Hole ◽  
Black Hole Candidates

AbstractThis paper investigates a recent model proposed by Moskalenko, Collmar & Schönfelder (1998) for the plasma surrounding galactic black hole candidates. Using a linear Monte Carlo code, the spectral and temporal behaviour of the model is found for the case where the plasma geometry consists of a hot shell surrounding a cooler spherical core. The spectrum produced by this model at X-ray and gamma-ray energies is obtained numerically. Also found for the first time in this geometry are the photon time-lags between two energy bands due to rapid aperiodic variability. It is argued that the time-lag information may be able to determine whether this particular geometry is a realistic model for the material surrounding galactic black hole candidates.

Gamma-ray monitoring of AGN and galactic black hole candidates by the gamma-ray observatory

1992 ◽  
Author(s):  
Wm. A. Wheaton ◽  
James C. Ling ◽  
R. T. Skelton ◽  
Alan Harmon ◽  
Gerald J. Fishman ◽  
...  
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Galactic Black Hole ◽  
Black Hole Candidates

scholarly journals Identifying the radiative components responsible for quasi-periodic oscillations of black hole systems

2020 ◽  
Vol 498 (2) ◽  
pp. 2757-2765
Author(s):  
Akash Garg ◽  
Ranjeev Misra ◽  
Somasri Sen
Keyword(s):  
Black Hole ◽  
Spectral Component ◽  
Temporal Variations ◽  
Time Lags ◽  
Temporal Data ◽  
Periodic Oscillations ◽  
Temporal Behaviour ◽  
Galactic Black Hole ◽  
Best Fitting ◽  
Energy Dependent

ABSTRACT While the dynamical origin of the variability observed in Galactic black hole systems, such as quasi-periodic oscillations (QPOs), is still a matter of debate, insight into the radiative components responsible for such behaviour can be obtained by studying their energy-dependent temporal behaviour. In particular, one needs to ascertain which variations of the parameters of the best-fitting time-averaged spectral components reproduce the observed energy-dependent fractional rms and time-lags. However, to obtain meaningful interpretation, the standard spectral component parameters have to be recast to physically relevant ones. Then, the energy-dependent temporal variations that their fluctuations will cause, needs to be predicted and compared with observations. In this work, we describe a generic method to do this and apply the technique to the ∼3–4 Hz QPOs observed in the black hole system GRS 1915+105 as observed by AstroSat where the time-averaged spectra can be represented by emission from a truncated disc and hot thermal Comptonizing coronae in the inner regions. We find that the QPOs and their harmonic can be explained in terms of correlated local accretion rate variations in the disc, the truncated disc radius, the optical depth and the heating rate of the coronae with time-delays between them. We highlight the potential of such techniques to unravel the radiative process responsible for variability using high-quality spectral and temporal data from AstroSat and NICER.

scholarly journals Gamma‐Ray Spectral States of Galactic Black Hole Candidates

1998 ◽  
Vol 500 (2) ◽  
pp. 899-908 ◽  
Author(s):  
J. E. Grove ◽  
W. N. Johnson ◽  
R. A. Kroeger ◽  
K. McNaron‐Brown ◽  
J. G. Skibo ◽  
...  
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Galactic Black Hole ◽  
Spectral States ◽  
Black Hole Candidates

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 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 Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1

Science ◽  
2011 ◽  
Vol 332 (6028) ◽  
pp. 438-439 ◽  
Author(s):  
P. Laurent ◽  
J. Rodriguez ◽  
J. Wilms ◽  
M. Cadolle Bel ◽  
K. Pottschmidt ◽  
...  
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Galactic Black Hole ◽  
Gamma Ray Emission
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