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We test the models of synchrotron emission presented in Part I of this series (Lloyd & Petrosian, these proceedings) against the distributions and evolution of GRB spectral parameters (particularly the low energy index, $\alpha$). With…
The prompt emission from GRBs is the brightest electromagnetic emission known yet it's origin is not understood. The flux density of individual prompt pulses of a GRB can be represented by an analytical expression derived assuming the…
GRB 090618 was simultaneously detected by Swift-BAT and Fermi-GBM. Its light curve shows two emission episodes consisting of four prominent pulses. The pulse in the first episode (episode A) has a smoother morphology than the three pulses…
Traditionally gamma-ray bursts (GRBs) are classified in the $T_{90}$-hardness ratio two-dimensional plane into long/soft and short/hard GRBs. In this paper, we suggest to add the "amplitude" of GRB prompt emission as the third dimension as…
The emission mechanism of the gamma-ray bursts (GRBs) is still a matter of debates. The standard synchrotron energy spectrum of cooling electrons F_E ~ E^{-1/2} is much too soft to account for the majority of the observed spectral slopes.…
The recent launches of the Einstein Probe (EP) and the Space Variable Objects Monitor (SVOM) mission have led to the detection of a growing number of long GRBs with significant, early soft X-ray flux during their gamma-ray emission,…
Recent Swift observations suggest that the traditional long vs. short GRB classification scheme does not always associate GRBs to the two physically motivated model types, i.e. Type II (massive star origin) vs. Type I (compact star origin).…
It is widely accepted that the prompt transient signal in the 10 keV - 10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and…
The origin of prompt emission in GRBs is not yet well understood. The simplest and most popular model is Synchrotron, Self-Compton (SSC) emission produced by internal shocks inside an ultra-relativistic jet. However, recent observations of…
After more than 40 years from their discovery, the long-lasting tension between predictions and observations of GRBs prompt emission spectra starts to be solved. We found that the observed spectra can be produced by the synchrotron process,…
A substantial fraction of prompt GRB spectra have soft spectral indexes exceeding the maximum allowed by the synchrotron model alpha_{max}=-2/3. Some spectra also exhibit very sharp break at E_p, inconsistent with the smooth synchrotron…
We have carried out a systematic analysis of the gamma-ray bursts' (GRBs) light curves detected in the SPI-ACS experiment onboard the INTEGRAL observatory aimed to search extended emission. The emission occasionally recorded after the…
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…
Simple hardness ratios are found to be a good estimator for the spectral peak energy in Gamma-Ray Bursts (GRBs). Specifically, a high correlation strength is found between the $\nu F_{\nu}$ peak in the spectrum of BATSE GRBs, $\epo$, and…
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…
We present the results of the spectral analysis of the public data of 438 Gamma Ray Bursts (GRBs) detected by the Fermi Gamma ray Burst Monitor (GBM) up to March 2010. For 432 bursts we could fit the time integrated spectrum. In 318 cases…
Gamma-ray bursts (GRBs) are widely believed to be from massive collapsars and/or compact binary mergers, which accordingly, would generate long and short GRBs, respectively. The details on this classification scheme have been in constant…
Type I gamma-ray bursts (GRBs) are believed to originate from compact binary merger usually with duration less than 2 seconds for the main emission. However, recent observations of GRB 211211A and GRB 230307A indicate that some…
We present the results of a comprehensive study of the luminosity function, energetics, prompt gamma-ray correlations, and classification methodology of short-hard and long-soft GRBs (SGRBs and LGRBs), based on observational data in the…
We consider the evidence for very hard low energy spectra during the prompt phase of Gamma Ray Bursts (GRB). In particular we examine the spectral evolution of GRB 980306 together with the detailed analysis of some other bursts already…