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The prompt emission of the long, smooth, and single-pulsed gamma-ray burst, GRB $\textit{141028A}$, is analyzed under the guise of an external shock model. First, we fit the $\gamma$-ray spectrum with a two-component photon model, namely…

High Energy Astrophysical Phenomena · Physics 2016-05-25 J. Michael Burgess , Damien Bégué , Felix Ryde , Nicola Omodei , Asaf Pe'er , J. L. Racusin , A. Cucchiara

Hot magnetic stars often exhibit incoherent circularly polarized radio emission thought to arise from gyro-synchrotron emission by energetic electrons trapped in the circumstellar magnetosphere. Theoretical scalings for electron…

Solar and Stellar Astrophysics · Physics 2023-08-16 B. Das , S. P. Owocki

We explore fitting gamma-ray burst spectra with three physically-motivated models, and thus revisit the viability of synchrotron radiation as the primary source of GRB prompt emission. We pick a sample of 100 bright GRBs observed by the…

High Energy Astrophysical Phenomena · Physics 2023-11-23 Suraj Poolakkil , Robert Preece , Peter Veres

The observations of the prompt emission of gamma ray bursts (GRB) by GLAST Burst Monitor (GBM), on board Fermi Gamma-ray Space Telescope, suggest the presence of a significant thermal spectral component, whose origin is not well understood.…

High Energy Astrophysical Phenomena · Physics 2017-03-29 Priya Bharali , Sunder Sahayanathan , Ranjeev Misra , Kalyanee Boruah

Using high-quality, broad-band afterglow data for GRB 091127, we investigate the validity of the synchrotron fireball model for gamma-ray bursts, and infer physical parameters of the ultra-relativistic outflow. We used multi-wavelength…

We consider the effects of inverse Compton scattering of synchrotron photons from relativistic electrons in GRB afterglows. We compute the spectrum of the inverse Compton emission and find that it can dominate the total cooling rate of the…

Astrophysics · Physics 2008-11-26 Re'em Sari , Ann A. Esin

Synchrotron polarization of relativistic nonthermal electrons in gamma-ray bursts (GRBs) has been widely studied. However, recent numerical simulations of relativistic shocks and magnetic reconnection have found that a more realistic…

High Energy Astrophysical Phenomena · Physics 2024-10-02 Kangfa Cheng , Jirong Mao , Xiaohong Zhao , Hongbang Liu , Merlin Kole , Nicolas Produit , Zhifu Chen

The dominant radiation mechanism that produces the prompt emission in gamma-ray bursts (GRBs) remains a major open question. Spectral information alone has proven insufficient in elucidating its nature. Time-resolved linear polarization has…

High Energy Astrophysical Phenomena · Physics 2021-04-21 Ramandeep Gill , Jonathan Granot

We explain the results of Yu et al. (2015b) of the novel sharpness angle measurement to a large number of spectra obtained from the Fermi gamma-ray burst monitor. The sharpness angle is compared to the values obtained from various…

Gamma-ray bursts (GRBs) are intense pulses of high-energy emission associated with massive stars' death or compact objects' coalescence. Their multi-wavelength observations help verify the reliability of the standard fireball model. We…

High Energy Astrophysical Phenomena · Physics 2024-11-19 M. G. Dainotti , S. Bhardwaj , E. Bissaldi , N. Fraija , S. Sourav , A. Galvan-Gamez

We discuss the spectrum arising from synchrotron emission by fast cooling (FC) electrons, when fresh electrons are continually accelerated by a strong blast wave, into a power law distribution of energies. The FC spectrum was so far…

Astrophysics · Physics 2009-10-31 Jonathan Granot , Tsvi Piran , Re'em Sari

Several trends have been identified in the prompt gamma-ray burst (GRB) emission: e.g. hard-to-soft evolution, pulse width evolution with energy, time lags, hardness-intensity/-fluence correlations. Recently Fermi has significantly extended…

High Energy Astrophysical Phenomena · Physics 2015-06-19 Z. Bosnjak , F. Daigne

The study of high-energy gamma-ray emission from gamma-ray bursts (GRBs) involves complex synchrotron radiation and synchrotron self-Compton scattering (SSC) mechanisms with multiple parameters exhibiting a wide distribution. Recent…

High Energy Astrophysical Phenomena · Physics 2024-12-25 Yu-Hua Yao , Fang-Sheng Min , Shi Chen , Yi-Qing Guo

We propose a new mechanism for the prompt emission of gamma-ray burst. In our model electrons are continuously accelerated in the post shock region via plasma turbulence. Using the Monte Carlo technique, we mimic the second-order Fermi…

High Energy Astrophysical Phenomena · Physics 2009-11-05 K. Asano , T. Terasawa

We aim to obtain a measure of the curvature of time-resolved spectra that can be compared directly to theory. This tests the ability of models such as synchrotron emission to explain the peaks or breaks of GBM prompt emission spectra. We…

We argue that small pitch angle synchrotron emission provides an important dissipation mechanism which has to be taken into account in the models of formation of relativistic magnetized gamma-ray burst (GRB) outflows from the newborn black…

High Energy Astrophysical Phenomena · Physics 2010-08-12 A. Neronov , V. Savchenko

Observations of TeV emission from early gamma-ray burst (GRB) afterglows revealed the long sought for inverse Compton (IC) upscattering of the lower energy synchrotron. However, it turned out that the long hoped for ability to easily…

High Energy Astrophysical Phenomena · Physics 2022-03-09 Shotaro Yamasaki , Tsvi Piran

The role of Compton cooling in the standard model for the afterglows of gamma-ray bursts is considered. When electrons cool by scattering off their own synchrotron photons, three cooling regimes are identified in which the observed…

Astrophysics · Physics 2009-11-06 C. -I. Bjornsson

I present a computationally efficient way to account for synchrotron and its inverse Compton scattered emission along with the resulting radiative losses, in a self-consistent way, for a relativistic distribution of electrons continuously…

Astrophysics · Physics 2007-05-23 H. Papathanassiou

Synchrotron self-Compton (SSC) scattering is an important emission mechanism in many astronomical sources, such as gamma-ray bursts (GRBs) and active galactic nuclei (AGNs). We give a complete presentation of the analytical approximations…

High Energy Astrophysical Phenomena · Physics 2015-06-04 He Gao , Wei-Hua Lei , Xue-Feng Wu , Bing Zhang
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