Related papers: Modeling Synchrotron Self-Compton and Klein-Nishin…
Although the physical origin of gamma-ray burst (GRB) prompt emission is still controversial, synchrotron radiation from accelerated electrons is a promising mechanism. It is believed that electrons are accelerated continuously by…
Analysis of observations with XMM-Newton have made a significant contribution to the study of Gamma-ray Burst (GRB) X-ray afterglows. The effective area, bandpass and resolution of the EPIC instrument permit the study of a wide variety of…
We model rapid variability of multifrequency emission from blazars occurring across the electromagnetic spectrum (from radio to gamma-rays). Lower energy emission is produced by the synchrotron mechanism, whereas higher energy emission is…
We calculate the synchrotron and inverse-Compton emissions from pairs formed in GRB afterglows from high-energy photons (above 100 MeV), assuming a power-law photon spectrum C_nu ~ nu^{-2} and considering only the pairs generated from…
The radiation from afterglows of gamma-ray bursts (GRB) is generated in collisionless plasma shocks. The two main ingredients behind the radiation are high-energy, non-thermal electrons and a strong magnetic field. I argue that in order to…
The Swift satellite has observed more than a thousand GRBs with X-ray data. Almost a third of them have redshift measurement, too. Here we start to investigate the X-ray spectral fitting of the data considering the low energy part where the…
The modelling of gamma-ray burst (GRB) spectra has considerable potential for increasing the understanding of these enigmatic sources. A diversity of ideas and analyses has been generated over the last two decades to explain line features…
The association of all three soft gamma-ray repeaters (SGRs) with supernova remnants has made possible estimates of the distance to and luminosity of the sources of SGRs, which have provided a starting point for detailed modeling. One of…
We discuss the effects of synchrotron self-absorption in the prompt emission from the reverse shock of GRB afterglows occurring in a dense environment, such as the wind of a massive stellar progenitor or a dense ISM in early galaxies. We…
In a recent paper (Dai & Lu 1999), we have proposed a simple model in which the steepening in the light curve of the R-band afterglow of the gamma-ray burst (GRB) 990123 is caused by the adiabatic shock which has evolved from an…
Gamma-ray Bursts (GRBs) generate powerful relativistic jets that inject a large amount of energy into their surrounding environment, producing blast waves that accelerate particles to high energies. The GRB afterglow radiation provides a…
Based on light curves from the Swift Burst Analyser, we investigate whether a `dip' feature commonly seen in the early-time hardness ratios of Swift-XRT data could arise from the juxtaposition of the decaying prompt emission and rising…
We examine a sample of 21 gamma-ray burst (GRB) afterglow light curves at radio frequencies, and compare them to the X-ray and/or optical properties of the afterglows and to the predictions of the standard jet/fireball model. Our sample…
We calculate the Compton scattering for photon and gluon with the Klein-Nishina formula in fixed-target collisions by using the proton and lead beams at AFTER@LHC. In these collisions, we can investigate the particular case of Compton…
We investigate a model for the shallow decay phases of Gamma-ray Burst (GRB) afterglows discovered by Swift/XRT in the first hours following a GRB event. In the context of the fireball scenario, we consider the possibility that long-lived…
PAPER WITHDRAWN. The recent detection of Sgr A* in the X-ray band, together with the radio polarization measurements conducted over the past few years, offer the best constraints yet for understanding the nature of the emitting gas within…
Swift discovered XRF 050416A with the BAT and began observing it with its narrow field instruments only 64.5 s after the burst onset. Its very soft spectrum classifies this event as an X-ray flash. The afterglow X-ray emission was monitored…
Radio, X-ray, and gamma-ray observations provide us with strong evidence of particle acceleration to multi-TeV energies in various astrophysical sources. Diffusive shock acceleration is one of the most successful models explaining the…
Scattering of the forward-shock synchrotron emission by a relativistic outflow located behind the leading blast-wave may produce an X-ray emission brighter than that coming directly from the forward-shock and may explain four features…
We develop a model to fit the broadband afterglows of GRBs from the intrinsic parameters of the fireball's synchrotron emission, and apply it to a few well-studied events, with the goal of constraining the intrinsic variability of GRB…