scholarly journals An Ultraviolet Excess in the Superluminous Supernova Gaia16apd Reveals a Powerful Central Engine

2017 ◽  
Vol 835 (1) ◽  
pp. L8 ◽  
Author(s):  
M. Nicholl ◽  
E. Berger ◽  
R. Margutti ◽  
P. K. Blanchard ◽  
D. Milisavljevic ◽  
...  
Keyword(s):  
Ultraviolet Excess ◽  
Central Engine

scholarly journals Interpreting the X-ray afterglows of gamma-ray bursts with radiative losses and millisecond magnetars

2020 ◽  
Vol 499 (4) ◽  
pp. 5986-5992
Author(s):  
Nikhil Sarin ◽  
Paul D Lasky ◽  
Gregory Ashton
Keyword(s):  
Gravitational Wave ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Dipole Radiation ◽  
X Ray ◽  
Radiative Efficiency ◽  
Central Engine ◽  
Radiative Losses ◽  
Wave Emission ◽  
Prompt Emission

ABSTRACT The spin-down energy of millisecond magnetars has been invoked to explain X-ray afterglow observations of a significant fraction of short and long gamma-ray bursts. Here, we extend models previously introduced in the literature, incorporating radiative losses with the spin-down of a magnetar central engine through an arbitrary braking index. Combining this with a model for the tail of the prompt emission, we show that our model can better explain the data than millisecond-magnetar models without radiative losses or those that invoke spin-down solely through vacuum dipole radiation. We find that our model predicts a subset of X-ray flares seen in some gamma-ray bursts. We can further explain the diversity of X-ray plateaus by altering the radiative efficiency and measure the braking index of newly born millisecond magnetars. We measure the braking index of GRB061121 as $n=4.85^{+0.11}_{-0.15}$ suggesting the millisecond-magnetar born in this gamma-ray burst spins down predominantly through gravitational-wave emission.

New galaxies with ultraviolet excess. IV

Astrophysics ◽  
1983 ◽  
Vol 18 (4) ◽  
pp. 285-296 ◽  
Author(s):  
M. A. Kazaryan ◽  
�. S. Kazaryan
Keyword(s):  
Ultraviolet Excess

scholarly journals GRB 060206: hints of precession of the central engine?

2008 ◽  
Vol 487 (2) ◽  
pp. 503-508 ◽  
Author(s):  
X. W. Liu ◽  
X. F. Wu ◽  
T. Lu
Keyword(s):  
Central Engine

scholarly journals Optical Afterglows as Probes for the Central Engine and Fireball of Gamma-Ray Bursts

2012 ◽  
Vol 8 (S290) ◽  
pp. 263-264
Author(s):  
Liang Li ◽  
En-Wei Liang ◽  
He Gao ◽  
Bing Zhang
Keyword(s):  
Statistical Analysis ◽  
Gamma Rays ◽  
Density Profile ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Gamma Ray Bursts ◽  
Prompt Gamma ◽  
Medium Density ◽  
Central Engine ◽  
Prompt Emission

AbstractWell-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are compiled from literature. We identify possible emission components based on our empirical fits and present statistical analysis for these components. We find that the flares are related to prompt emission, suggesting that they could have the same origin in different episodes. The shallow decay segment is not correlated with prompt gamma-rays. It likely signals a long-lasting injected wind from GRB central engines. Early after onset peak is closely related with prompt emission. The ambient medium density profile is likely n ∝ r−1. No correlation between the late re-brightening bump and prompt gamma-rays or the onset bump is found. They may be from another jet component.

Morphology of some new galaxies with ultraviolet excess

Astrophysics ◽  
1987 ◽  
Vol 26 (3) ◽  
pp. 249-252
Author(s):  
V. S. Tamazyan
Keyword(s):  
Ultraviolet Excess

STRUCTURE AND EMISSION OF COMPACT BLAZAR JETS

2012 ◽  
Vol 08 ◽  
pp. 151-162 ◽  
Author(s):  
ALAN P. MARSCHER
Keyword(s):  
Millimeter Wave ◽  
Position Angle ◽  
Turbulent Plasma ◽  
Time Variability ◽  
Relativistic Jets ◽  
X Ray ◽  
The Core ◽  
Central Engine ◽  
Conical Shock ◽  
Jet Plasma

Relativistic jets in blazars on parsec scales can now be explored with direct imaging at radio wavelengths as well as observations of time variability of flux and linear polarization at various wavebands. The results thus far suggest that the millimeter-wave "core" is usually a standing, conical shock and that the jet plasma is turbulent. Disturbances and turbulent plasma crossing the standing shock can explain much of the observed variability, as well as the appearance of bright knots moving down the jet at superluminal apparent speeds. The core, located parsecs downstream of the central engine, appears to be the site of many of the outbursts observed at optical, X-ray, and γ-ray energies. Rotations in the optical polarization position angle prior to the passage of a knot through the millimeter-wave core provide evidence for helical magnetic fields that accelerate and collimate the jet before turbulence tangles the fields.

scholarly journals Fueling the central engine of radio galaxies

2007 ◽  
Vol 468 (3) ◽  
pp. L71-L75 ◽  
Author(s):  
S. García-Burillo ◽  
F. Combes ◽  
R. Neri ◽  
A. Fuente ◽  
A. Usero ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Central Engine

scholarly journals A NARROW SHORT-DURATION GRB JET FROM A WIDE CENTRAL ENGINE

2015 ◽  
Vol 813 (1) ◽  
pp. 64 ◽  
Author(s):  
Paul C. Duffell ◽  
Eliot Quataert ◽  
Andrew I. MacFadyen
Keyword(s):  
Short Duration ◽  
Central Engine
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