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Related papers: The Spectral Sharpness Angle of Gamma-ray Bursts

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The Fermi observatory, with its Gamma-Ray Bursts monitor (GBM) and Large Area Telescope (LAT), is observing Gamma-ray Bursts with unprecedented spectral coverage and sensitivity, from ~10 keV to > 300 GeV. In the first 3 years of the…

High Energy Astrophysical Phenomena · Physics 2013-05-27 Giacomo Vianello

The degree to which gamma ray bursts are collimated is now the dominant uncertainty in their energy requirements and event rates. In this review I begin with the reasons for studying GRB collimation, then discuss existing tests for…

Astrophysics · Physics 2017-08-23 James E. Rhoads

From July 2008 to October 2009, the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope (FGST) has detected 320 Gamma-Ray Bursts (GRBs). About 20% of these events are classified as short based on their T90 duration…

We present time resolved spectral analysis of prompt emission from GRB 160625B, one of the brightest bursts ever detected by Fermi in its nine years of operations. Standard empirical functions fail to provide an acceptable fit to the GBM…

High Energy Astrophysical Phenomena · Physics 2018-05-30 M. E. Ravasio , G. Oganesyan , G. Ghirlanda , L. Nava , G. Ghisellini , A. Pescalli , A. Celotti

The spectral width and sharpness of unfolded, observed GRB spectra have been presented as a new tool to infer physical properties about GRB emission via spectral fitting of empirical models. Following the tradition of the 'line-of-death',…

High Energy Astrophysical Phenomena · Physics 2019-09-11 J. Michael Burgess

Studying the GRBs' gamma-ray spectra may reveal some physical information of Gamma-ray Bursts. The Fermi satellite observed more than two thousand GRBs. The FERMIGBRST catalog contains GRB parameters (peak energy, spectral indices,…

High Energy Astrophysical Phenomena · Physics 2019-09-06 Istvan I. Racz , Lajos G. Balázs , Zsolt Bagoly , Istvan Horvath , L. Viktor Tóth

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…

High Energy Astrophysical Phenomena · Physics 2015-05-20 L. Nava , G. Ghirlanda , G. Ghisellini , A. Celotti

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

After almost 4 years of operation, the two instruments onboard the Fermi Gamma-ray Space Telescope have shown that the number of gamma-ray bursts with high energy photon emission above 100 MeV cannot exceed roughly 9% of the total number of…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Carl W. Akerlof , WeiKang Zheng

We constrain the distance of the Gamma-Ray Burst (GRB) prompt emission site from the explosion centre, R, by determining the location of the electron's self absorption frequency in the GRB prompt optical-to-X/gamma-ray spectral energy…

High Energy Astrophysical Phenomena · Physics 2014-03-11 Rong-Feng Shen , Bing Zhang

We performed time-resolved spectroscopy on a sample of 38 single pulses from 37 gamma-ray bursts detected by the Fermi/Gamma-ray Burst Monitor during its first 9 years of mission. For the first time a fully Bayesian approach is applied. A…

High Energy Astrophysical Phenomena · Physics 2020-01-08 Hoi-Fung Yu , Hüsne Dereli-Bégué , Felix Ryde

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…

High Energy Astrophysical Phenomena · Physics 2019-06-12 Zeynep Acuner , Felix Ryde , Hoi-Fung Yu

We present the results of the spectral analysis of a sample of short bright $\gamma$--ray bursts (GRB) detected by BATSE and compare them with the average and time resolved spectral properties of long bright bursts. While the spectral…

Astrophysics · Physics 2009-11-10 G. Ghirlanda , G. Ghisellini , A. Celotti

The detection in 10 bursts of an optical counterpart emission (i.e. during the prompt GRB phase) that is 10-10000 brighter than the extrapolation of the burst spectrum to optical frequencies suggests a synchrotron self-Compton origin for…

Astrophysics · Physics 2008-11-11 A. Panaitescu

Aims. The aim of the study is to constrain the physics of gamma-ray bursts (GRBs) by analysing the multi-wavelength afterglow data set of GRB 121024A that covers the full range from radio to X-rays. Methods. Using multi-epoch broad-band…

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…

Astrophysics · Physics 2009-10-28 M. G. Baring

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…

High Energy Astrophysical Phenomena · Physics 2015-06-16 D. Kopac , S. Kobayashi , A. Gomboc , J. Japelj , C. G. Mundell , C. Guidorzi , A. Melandri , D. Bersier , Z. Cano , R. J. Smith , I. A. Steele , F. J. Virgili

The time-resolved spectra of gamma-ray bursts (GRBs) remain in conflict with many proposed models for these events. After proving that most of the bursts in our sample show evidence for spectral "shape-shifting", we discuss what…

Astrophysics · Physics 2009-10-30 A. Crider , E. P. Liang , R. D. Preece

In this catalog we present the updated set of spectral analyses of GRBs detected by the Fermi Gamma-Ray Burst Monitor (GBM) during its first four years of operation. It contains two types of spectra, time-integrated spectral fits and…

We compare the spectral properties of 227 Gamma Ray Bursts (GRBs) detected by the Fermi Gamma Ray Burst Monitor (GBM) up to February 2010 with those of bursts detected by the CGRO/BATSE instrument. Out of 227 Fermi GRBs, 166 have a measured…

High Energy Astrophysical Phenomena · Physics 2010-04-12 L. Nava , G. Ghirlanda , G. Ghisellini , A. Celotti