scholarly journals Afterglow light curves from magnetized GRB flows

2010 ◽  
Vol 6 (S275) ◽  
pp. 358-362
Author(s):  
Petar Mimica ◽  
Dimitrios Giannios ◽  
Miguel Ángel Aloy
Keyword(s):  
Magnetic Field ◽  
Radiative Transfer ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Light Curves ◽  
Reverse Shock ◽  
The Magnetic Field

AbstractUsing the RMHD code MRGENESIS and the radiative transfer code SPEV we compute multiwavelength afterglow light curves of magnetized ejecta of gamma-ray bursts interacting with a uniform circumburst medium. We are interested in the emission from the reverse shock when ejecta magnetization varies from σ0 = 0 to σ0 = 1. For typical parameters of the ejecta, the emission from the reverse shock peaks for magnetization σ0 ~ 0.01 − 0.1, and is suppressed for higher σ0. We fit the early afterglow light curves of GRB 990123 and 090102 and discuss the possible magnetization of the outflows of these bursts. Finally we discuss the amount energy left in the magnetic field which is available for dissipation at later afterglow stages.

SIMULATIONS OF DYNAMICS AND EMISSION FROM MAGNETIZED GRB AFTERGLOWS

2010 ◽  
Vol 19 (06) ◽  
pp. 985-990 ◽  
Author(s):  
PETAR MIMICA ◽  
DIMITRIOS GIANNIOS ◽  
MIGUEL ANGEL ALOY
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Field Strength ◽  
Light Curves ◽  
Reverse Shock ◽  
Ultrahigh Resolution ◽  
Mhd Simulations ◽  
The Magnetic Field ◽  
Early Phases

The role of magnetic fields in the GRB flow is still controversial. The afterglow emission, particularly the early phases, may provide a probe into the magnetization of the outflow. Using ultrahigh resolution relativistic MHD simulations, the interaction between radially expanding magnetized ejecta with the interstellar medium is studied. We explore the effect of the magnetic field strength of the ejecta on the afterglow structure, particularly regarding the presence and strength of a reverse shock. We compute synthetic afterglow light curves to quantify the effect of the magnetization of the flow on observed radiation.

Can Precessing Jets Explain the Light Curves of Gamma‐Ray Bursts?

1999 ◽  
Vol 520 (2) ◽  
pp. 666-679 ◽  
Author(s):  
Simon F. Portegies Zwart ◽  
Chang‐Hwan Lee ◽  
Hyun Kyu Lee
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Light Curves

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.

scholarly journals Reverse Shock Emission in Gamma-Ray Bursts Revisited

2015 ◽  
Vol 2015 ◽  
pp. 1-16 ◽  
Author(s):  
He Gao ◽  
Peter Mészáros
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Shock Model ◽  
Intrinsic Properties ◽  
Reverse Shock

A generic synchrotron external shock model is the widely preferred paradigm used to interpret the broadband afterglow data of gamma-ray bursts (GRBs), including predicted observable signatures from a reverse shock which have been confirmed by observations. Investigations of the nature of the reverse shock emission can provide valuable insights into the intrinsic properties of the GRB ejecta. Here we briefly review the standard and the extended models of the reverse shock emission, discussing the connection between the theory and observations, including the implications of the latest observational advances.

scholarly journals Millimeter and Microwave Activity of the Sun

1990 ◽  
Vol 142 ◽  
pp. 457-465 ◽  
Author(s):  
M. R. Kundu ◽  
S. M. White
Keyword(s):  
Magnetic Field ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
High Spatial Resolution ◽  
High Resolution Imaging ◽  
The Sun ◽  
Millimeter Wavelengths ◽  
Resolution Imaging ◽  
The Magnetic Field

The emission of solar flares at millimeter wavelengths is of great interest both in its own right and because it is generated by the energetic electrons which also emit gamma rays. Since high-resolution imaging at gamma-ray energies is not presently possible, millimeter observations can act as a substitute. Except for that class of flares known as gamma-ray flares the millimetric emission is optically thin. It can be used as a powerful diagnostic of the energy distribution of electrons in solar flares and its evolution, and of the magnetic field. We have carried out high-spatial-resolution millimeter observations of solar flares this year using the Berkeley-Illinois-Maryland Array (BIMA), and report on the preliminary results in this paper (Kundu et al 1990; White et al 1990). We also report some recent results obtained from multifrequency observations using the VLA (White et al 1990).

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