Thermal hard X-ray and gamma ray emission of disk-accreting black holes

1993 ◽  
Author(s):  
Edison P. Liang
Keyword(s):  
Black Holes ◽  
Gamma Ray ◽  
X Ray ◽  
Gamma Ray Emission

LONG-TERM MONITORING OF THE HARD X-RAY/GAMMA-RAY EMISSION FROM GALACTIC BLACK HOLES WITH BATSE

2008 ◽  
Author(s):  
G. L. CASE ◽  
E. ANZALONE ◽  
M.L. CHERRY ◽  
J. C. RODI ◽  
J. C. LING ◽  
...  
Keyword(s):  
Black Holes ◽  
Gamma Ray ◽  
X Ray ◽  
Long Term Monitoring ◽  
Gamma Ray Emission ◽  
Term Monitoring

A Combined Model for the X‐Ray to Gamma‐Ray Emission of Cygnus X‐1

1998 ◽  
Vol 502 (1) ◽  
pp. 428-436 ◽  
Author(s):  
Igor V. Moskalenko ◽  
Werner Collmar ◽  
Volker Schonfelder
Keyword(s):  
Gamma Ray ◽  
Combined Model ◽  
X Ray ◽  
Gamma Ray Emission

scholarly journals Diverse Features of the Multiwavelength Afterglows of Gamma-Ray Bursts: Natural or Special?

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
J. J. Geng ◽  
Y. F. Huang
Keyword(s):  
Black Holes ◽  
Numerical Method ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Shock Model ◽  
Reverse Shock ◽  
X Ray ◽  
Electron Positron ◽  
Forward Shock ◽  
Electron Positron Pair

The detection of optical rebrightenings and X-ray plateaus in the afterglows of gamma-ray bursts (GRBs) challenges the generic external shock model. Recently, we have developed a numerical method to calculate the dynamics of the system consisting of a forward shock and a reverse shock. Here, we briefly review the applications of this method in the afterglow theory. By relating these diverse features to the central engines of GRBs, we find that the steep optical rebrightenings would be caused by the fall-back accretion of black holes, while the shallow optical rebrightenings are the consequence of the injection of the electron-positron-pair wind from the central magnetar. These studies provide useful ways to probe the characteristics of GRB central engines.

Sigma upper limits to the hard X-ray/soft gamma-ray emission from the millisecond pulsars of the nearby globular cluster 47 Tucunae

1993 ◽  
Vol 405 ◽  
pp. L59 ◽  
Author(s):  
D. Barret ◽  
P. Mandrou ◽  
M. Denis ◽  
J. F. Olive ◽  
P. Laurent ◽  
...  
Keyword(s):  
Globular Cluster ◽  
Gamma Ray ◽  
Millisecond Pulsars ◽  
X Ray ◽  
Upper Limits ◽  
Gamma Ray Emission

scholarly journals X-ray and Gamma-ray Variability of NGC 1275

Galaxies ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 63
Author(s):  
Varsha Chitnis ◽  
Amit Shukla ◽  
K. P. Singh ◽  
Jayashree Roy ◽  
Sudip Bhattacharyya ◽  
...  
Keyword(s):  
Time Scales ◽  
Gamma Ray ◽  
Radio Galaxy ◽  
Cluster Emission ◽  
X Ray ◽  
Gamma Ray Emission ◽  
High Degree ◽  
Ngc 1275 ◽  
Perseus Cluster ◽  
Very High

Gamma-ray emission from the bright radio source 3C 84, associated with the Perseus cluster, is ascribed to the radio galaxy NGC 1275 residing at the centre of the cluster. Study of the correlated X-ray/gamma-ray emission from this active galaxy, and investigation of the possible disk-jet connection, are hampered because the X-ray emission, particularly in the soft X-ray band (2–10 keV), is overwhelmed by the cluster emission. Here we present a method to spectrally decouple the cluster and active galactic nucleus (AGN) emission in imaging X-ray detectors. We use three sets of simultaneous Niel Gehrels Swift XRT and NuStar data. These observations were made during the period 2015 November to 2017 February, when a huge increase in the gamma-ray emission was observed. We find that the gamma-ray emission shows a very high degree of variability (40%–50%) on time scales of 1–10 days, whereas the hard X-ray emission, associated with the AGN, shows a low variability (∼15%–30%), on various time scales in the range of 0.01–60 days.

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