Related papers: Time Resolved GRB Spectroscopy
We have developed an automatic search procedure to identify low-energy spectral features in GRBs. We have searched 133,000 spectra from 117 bright bursts and have identified 12 candidate features with significances ranging from our…
We examine the rest frame energetics of 76 gamma-ray bursts (GRBs) with known redshift that were detected by the Swift spacecraft and monitored by the satellite's X-ray Telescope (XRT). Using the bolometric fluence values estimated in…
Our recent studies of Very Short Gamma Ray Bursts (VSB) of duration T_{90} \le 100 ms have indicated a significant angular asymmetry and a uniform V/V_{max} distribution from the BATSE data. Here we update these studies, and we extend our…
We present the main results of a study of spectral and energetics properties of twelve gamma-ray bursts (GRBs) with redshift estimates. All GRBs in our sample were detected by BeppoSAX in a broad energy range (2-700 keV). From the redshift…
The Gamma-Ray Optical Counterpart Search Experiment (GROCSE) presents new experimental upper limits on the optical flux from gamma-ray bursts (GRBs). Our experiment consisted of a fully-automated very wide-field opto-electronic detection…
We reexamine the general synchrotron model for GRBs' prompt emission and determine the regime in the parameter phase space in which it is viable. We characterize a typical GRB pulse in terms of its peak energy, peak flux and duration and…
Under the steady state condition, the spectrum of electrons is investigated by solving the continuity equation under the complex radiation of both the synchrotron and Compton processes. The resulted GRB spectrum is a broken power law in…
The connection between Gamma-Ray Bursts (GRBs) and their afterglows is currently not well understood. Afterglow models of synchrotron emission generated by external shocks in the GRB fireball model predict emission detectable in the…
A large fraction of gamma-ray burst (GRB) spectra are very hard below the peak. Indeed, the observed distribution of sub-peak power-law indices, $\alpha$, has been used as an argument for a photospheric origin of GRB spectra. Here, we…
Long gamma-ray bursts (GRBs) are the most luminous known electromagnetic radiation sources in the Universe for the 3 to 300 sec of their prompt flashes (isotropic X/ gamma-ray luminosities up to 10^53 ergs/sec). Their afterglows have first…
Gamma-ray burst (GRB) spectra are typically non-thermal, with many including two spectral breaks suggestive of optically-thin emission. However, the emitted spectrum from a GRB photosphere, which includes prior dissipation of energy by…
There is no complete description of the emission physics during the prompt phase in gamma-ray bursts. Spectral analyses, however, indicate that many spectra are narrower than what is expected for non-thermal emission models. Here, we…
We present a time-resolved spectral analysis of 51 long and 11 short bright GRBs observed with the {\em Femri}/GBM, paying special attention to $E_{\rm p}$ evolution within a same burst. Among 8 single-pulse long GRBs, 5 show hard-to-soft…
We present a multi-wavelength analysis of gamma-ray burst GRB 090727, for which optical emission was detected during the prompt gamma-ray emission by the 2-m autonomous robotic Liverpool Telescope and subsequently monitored for a further…
Aims: Gamma Ray Bursts (GRBs) are sometimes preceded by dimmer emission episodes, called "precursors", whose nature is still a puzzle: they could either have the same origin as the main emission episode or they could be due to another…
Using the gamma-ray bursts simultaneously detected by Swift/BAT and Fermi/GBM we performed a joint spectral and temporal analysis of the prompt emission data and confirm the rough correlation between the BAT-band photon index Gamma_BAT and…
We use a parent sample of 118 gamma-ray burst (GRB) afterglows, with known redshift and host galaxy extinction, to separate afterglows with and without signatures of dominant reverse-shock emission and to determine which physical conditions…
We investigated the spectral evolution in the 2--700 keV energy band of Gamma-Ray Bursts (GRBs) detected by the Gamma-Ray Burst Monitor (GRBM) and localized with the Wide Field Cameras (WFCs) aboard the BeppoSAX satellite before May 1998.…
We present the systematic spectral analyses of gamma-ray bursts (GRBs) detected by the Fermi Gamma-Ray Burst Monitor (GBM) during its first ten years of operation. This catalog contains two types of spectra; time-integrated spectral fits…
This is the first in a series of gamma-ray burst spectroscopy catalogs from the Burst And Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory, each covering a different aspect of burst phenomenology. In this paper, we…