scholarly journals Gamma-Ray Bursts Polarization

2016 ◽  
Vol 12 (S324) ◽  
pp. 54-61
Author(s):  
Diego Götz ◽  
Stefano Covino
Keyword(s):  
Black Hole ◽  
Kinetic Energy ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Central Source ◽  
Poynting Flux ◽  
Relativistic Jet ◽  
Theoretical Status ◽  
Prompt Emission ◽  
Open Point

AbstractWe review the current observational and theoretical status of the polarization measurements of Gamma-ray Bursts at all wavelengths. Gamma-Ray Bursts are thought to be produced by an ultra-relativistic jet, possibly powered by a black hole. One of the most important open point is the composition of the jet: the energy may be carried out from the central source either as kinetic energy (of baryons and/or pairs), or in electromagnetic form (Poynting flux). The polarization properties are expected to help disentangling main energy carrier. The prompt emission and afterglow polarization are also a powerful diagnostic of the jet geometry.

THE CASE FOR NON-BARYONIC ENERGY AS THE PRIMARY OUTPUT OF GRBs

2008 ◽  
Vol 17 (09) ◽  
pp. 1333-1341
Author(s):  
D. EICHLER
Keyword(s):  
Kinetic Energy ◽  
Photon Energy ◽  
Radiation Pressure ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Light Curves ◽  
Poynting Flux ◽  
Primary Output ◽  
Primary Form

The evidence is reviewed that the primary form of energy that escapes to infinity from gamma-ray bursts (GRBs) is gamma-rays, and/or Poynting flux, and that the kinetic energy in ultrarelativistic baryons is a secondary component resulting from acceleration of baryons by radiation pressure near or beyond the photosphere. This could account for several observed characteristics of observed GRB spectra and light curves, such as the typical peak photon energy, the correlation of this peak with apparent GRB energy, and the profiles and spectral lagging of GRB subpulses.

scholarly journals Evolution of an electron-positron plasma produced by induced gravitational collapse in binary-driven hypernovae

2018 ◽  
Vol 168 ◽  
pp. 04009 ◽  
Author(s):  
J. D. Melon Fuksman ◽  
L. Becerra ◽  
C. L. Bianco ◽  
M. Karlica ◽  
M. Kovacevic ◽  
...  
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gravitational Collapse ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Relativistic Hydrodynamics ◽  
X Ray ◽  
The Past ◽  
Electron Positron ◽  
Prompt Emission

The binary-driven hypernova (BdHN) model has been introduced in the past years, to explain a subfamily of gamma-ray bursts (GRBs) with energies Eiso ≥ 1052 erg associated with type Ic supernovae. Such BdHNe have as progenitor a tight binary system composed of a carbon-oxigen (CO) core and a neutron star undergoing an induced gravitational collapse to a black hole, triggered by the CO core explosion as a supernova (SN). This collapse produces an optically-thick e+e- plasma, which expands and impacts onto the SN ejecta. This process is here considered as a candidate for the production of X-ray flares, which are frequently observed following the prompt emission of GRBs. In this work we follow the evolution of the e+e- plasma as it interacts with the SN ejecta, by solving the equations of relativistic hydrodynamics numerically. Our results are compatible with the Lorentz factors estimated for the sources that produce the flares, of typically Γ ≲ 4.

scholarly journals Gamma Ray Bursts as Death of Magnetized Neutron Stars

1996 ◽  
Vol 160 ◽  
pp. 361-362
Author(s):  
Hitoshi Hanami
Keyword(s):  
Magnetic Field ◽  
Black Hole ◽  
Neutron Star ◽  
Neutron Stars ◽  
Strong Magnetic Field ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Final Phase ◽  
Poynting Flux ◽  
Free Process

AbstractWe propose magnetic cannon ball mechanism in which the collapse of a magnetosphere onto a black hole can generate strong outward Poynting flux which can drive a baryon-free fireball. This process can occur at the final collapsing phase of a neutron star with strong magnetic field. The magnetic cannon ball can drive a relativistic outflow without the rotation of the central object. This baryon-free process can explain gamma-ray bursts as the final phase of dead pulsars.

scholarly journals High efficiency photospheric emission entailed by formation of a collimation shock in gamma-ray bursts

2019 ◽  
Vol 488 (1) ◽  
pp. 1416-1426 ◽  
Author(s):  
Ore Gottlieb ◽  
Amir Levinson ◽  
Ehud Nakar
Keyword(s):  
High Efficiency ◽  
Gamma Ray ◽  
Surrounding Medium ◽  
Emission Spectra ◽  
Lorentz Factor ◽  
Gamma Ray Bursts ◽  
Opening Angle ◽  
Radiative Efficiency ◽  
Relativistic Jet ◽  
Prompt Emission

ABSTRACT The primary dissipation mechanism in jets of gamma-ray bursts (GRBs), and the high efficiency of the prompt emission are long-standing issues. One possibility is strong collimation of a weakly magnetized relativistic jet by the surrounding medium, which can considerably enhance the efficiency of the photospheric emission. We derive a simple analytic criterion for the radiative efficiency of a collimated jet showing that it depends most strongly on the baryon loading. We confirm this analytic result by 3D numerical simulations, and further find that mixing of jet and cocoon material at the collimation throat leads to a substantial stratification of the outflow as well as sporadic loading, even if the injected jet is uniform and continuous. One consequence of this mixing is a strong angular dependence of the radiative efficiency. Another is large differences in the Lorentz factor of different fluid elements that lead to formation of internal shocks. Our analysis indicates that in both long and short GRBs a prominent photospheric component cannot be avoided when observed within an angle of a few degrees to the axis, unless the asymptotic Lorentz factor is limited by baryon loading at the jet base to Γ∞ < 100 (with a weak dependence on outflow power). Photon generation by newly created pairs behind the collimation shock regulates the observed temperature at $\sim 50~\theta _0^{-1}$ keV, where θ0 is the initial jet opening angle, in remarkable agreement with the observed peak energies of prompt emission spectra. Further consequences for the properties of the prompt emission are discussed at the end.

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.

scholarly journals Variabilities of gamma-ray bursts from black hole hyper-accretion discs

2016 ◽  
Vol 463 (1) ◽  
pp. 245-250 ◽  
Author(s):  
Da-Bin Lin ◽  
Zu-Jia Lu ◽  
Hui-Jun Mu ◽  
Tong Liu ◽  
Shu-Jin Hou ◽  
...  
Keyword(s):  
Black Hole ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Accretion Discs

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.

scholarly journals Formation Rates of Black Hole Accretion Disk Gamma‐Ray Bursts

1999 ◽  
Vol 526 (1) ◽  
pp. 152-177 ◽  
Author(s):  
Chris L. Fryer ◽  
S. E. Woosley ◽  
Dieter H. Hartmann
Keyword(s):  
Black Hole ◽  
Accretion Disk ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Black Hole Accretion ◽  
Black Hole Accretion Disk ◽  
Hole Accretion

scholarly journals Pulsations in short gamma ray bursts from black hole-neutron star mergers

2013 ◽  
Vol 87 (8) ◽  
Author(s):  
Nicholas Stone ◽  
Abraham Loeb ◽  
Edo Berger
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Gamma Ray ◽  
Gamma Ray Bursts
Sign in / Sign up

Export Citation Format

Share Document