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The two widely accepted classes of gamma-ray bursts (GRBs), short and long, are with confidence ascribed to mergers of compact objects and collapse of massive stars, respectively. A third, intermediate/soft class, remains putative. Its…

High Energy Astrophysical Phenomena · Physics 2019-01-23 Mariusz Tarnopolski

The mechanism responsible for the prompt emission of gamma-ray bursts (GRBs) is still a debated issue. The prompt phase-related GRB correlations can allow to discriminate among the most plausible theoretical models explaining this emission.…

High Energy Astrophysical Phenomena · Physics 2018-02-01 Maria Dainotti , Roberta Del Vecchio , Mariusz Tarnopolski

We present here our results of the temporal and spectral analysis of a sample of 52 bright and hard gamma-ray bursts (GRBs) observed with the Fermi Gamma-ray Burst Monitor (GBM) during its first year of operation (July 2008-July 2009). Our…

Observations of Gamma-Ray Bursts with the Fermi Large Area Telescope have prompted theoretical advances and posed big challenges in the understanding of such extreme sources, despite the fact that GRB emission above 100 MeV is a fairly rare…

High Energy Astrophysical Phenomena · Physics 2015-02-12 Giacomo Vianello , Nicola Omodei , Fermi/LAT collaboration

Statistical studies of gamma-ray burst (GRB) spectra may result in important information on the physics of GRBs. The Fermi GBM catalog contains GRB parameters (peak energy, spectral indices, intensity) estimated fitting the gamma-ray SED of…

High Energy Astrophysical Phenomena · Physics 2017-12-29 Istvan I. Racz , Lajos G. Balázs , Istvan Horvath , L. Viktor Toth , Zsolt Bagoly

The light curves of Gamma-Ray Bursts (GRBs) are believed to result from internal shocks reflecting the activity of the GRB central engine. Their temporal deconvolution can reveal potential differences in the properties of the central…

Gamma-ray bursts (GRBs) are detectable out to very large distances and as such are potentially powerful cosmological probes. Historically, the angular distribution of GRBs provided important information about their origin and physical…

High Energy Astrophysical Phenomena · Physics 2015-11-11 T. N. Ukwatta , P. R. Wozniak

This paper introduces a method for studying the correlation structure of a range of responses modelled by a multivariate generalised linear mixed model (MGLMM). The methodology requires the existence of clusters of observations and that…

Methodology · Statistics 2021-08-02 Jeanett S. Pelck , Rodrigo Labouriau

Gamma-ray bursts (GRBs) are challenging to identify due to their transient nature, complex temporal profiles, and limited observational datasets. We address this with a one-dimensional convolutional neural network integrated with an…

Gamma-ray bursts (GRBs) show a bimodal distribution of durations, separated at a duration of ~2 s. Observations have confirmed the association of long GRBs with the collapse of massive stars. The origin of short GRBs is still being…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Anna Barnacka , Abraham Loeb

Gamma Ray Burst (GRBs) are empirically classified as long-duration GRBs (LGRBs, $>$ 2s) and short-duration GRBs (SGRBs, $<$ 2s). Physically they can be grouped into two distinct progenitor categories: those originating from collapse of…

High Energy Astrophysical Phenomena · Physics 2020-07-22 Ye Li , Bing Zhang , Qiang Yuan

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

In the external shock model, gamma-ray burst (GRB) emissions are produced by the energization and deceleration of a thin relativistic blast wave due to its interactions with the circumburst medium (CBM). We study the physical properties of…

Astrophysics · Physics 2009-10-31 Charles D. Dermer , Markus Boettcher , J. Chiang

We present a spectral analysis for a sample of redshift known GRBs observed with {\em Fermi}/GBM. Together with the results derived from our systematical spectral energy distribution modeling with the leptonic models for a {\em Fermi}/LAT…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Fen Lyu , En-Wei Liang , Yun-Feng Liang , Xue-Feng Wu , Jin Zhang , Xiao-Na Sun , Rui-Jing Lu , Bing Zhang

We are integrating the Fermi Gamma-Ray Burst Monitor (GBM) into the Interplanetary Network (IPN) of Gamma-Ray Burst (GRB) detectors. With the GBM, the IPN will comprise 9 experiments. This will 1) assist the Fermi team in understanding and…

Two classes of Gamma Ray Bursts have been identified so far, characterized by T_90 durations shorter and longer than approximately 2 seconds. We show here that the BATSE 3B data allow a good fit with three Gaussian distributions in log…

Astrophysics · Physics 2007-05-23 I. Horvath

Identification of gravitationally lensed Gamma Ray Bursts (GRBs) in the BATSE 4B catalog can be used to constrain the average redshift $ < z >$ of the GRBs. In this paper we investigate the effect of evolving lenses on the $< z >$ of GRBs…

Astrophysics · Physics 2009-10-31 Deepak Jain , N. Panchapakesan , S. Mahajan , V. B. Bhatia

The Large Area Telescope (LAT) on-board the Fermi satellite detected emission above 20 MeV only in a small fraction of the long gamma-ray bursts (GRBs) detected by the Fermi Gamma-ray Burst Monitor (GBM) at 8 keV-40 MeV. Those bursts that…

High Energy Astrophysical Phenomena · Physics 2013-03-08 Dafne Guetta

Tight constraints on cosmological parameters can be obtained with standard candles spanning a range of redshifts as large as possible. We propose to treat SN Ia and long Gamma-Ray Bursts (GRBs) as a single class of candles. Taking advantage…

Astrophysics · Physics 2007-05-23 C. Firmani , V. Avila-Reese , G. Ghisellini , G. Ghirlanda

We systematically compare the temporal and spectral properties of 53 Supernova (SN)-associated and 15 Kilonova (KN)-associated Gamma-Ray Bursts (GRBs). We find that the spectral parameters of both types GRBs are identically and lognormally…

High Energy Astrophysical Phenomena · Physics 2023-09-19 Q. M. Li , Z. B. Zhang , X. L. Han , K. J. Zhang , X. L. Xia , C. T. Hao