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Related papers: Bayesian Time-Resolved Spectroscopy of GRB Pulses

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We make a detailed pulse-wise study of gamma-ray bursts (GRBs) with known redshift detected by \emph{Fermi}/Gamma Ray Burst Monitor (GBM). The sample contains 19 GRBs with 43 pulses. We find that the average peak energy is correlated to the…

High Energy Astrophysical Phenomena · Physics 2015-06-17 Rupal Basak , A. R. Rao

The jet compositions of gamma-ray bursts (GRBs) are very important to understand the energy dissipation and radiation mechanisms, but it remains an open question in GRB physics. In this paper, we present a systematic analysis to search for…

High Energy Astrophysical Phenomena · Physics 2026-01-09 Xue-Zhao Chang , HouJun Lü , Zhao-Wei Du , Xing Yang , En-Wei Liang

Using an \emph{empirical} description of a prompt GRB pulse, we analyze the individual pulses of all Fermi/GBM GRBs with known redshifts, till July 2009. This description is simultaneous in time and energy and allows one to determine the…

High Energy Astrophysical Phenomena · Physics 2012-07-10 Rupal Basak , A. R. Rao

The analysis of gamma-ray burst (GRB) spectra often relies on empirical models lacking a distinct physical explanation. Previous attempts to couple physical models with observed data focus on individual burst studies, fitting models to…

High Energy Astrophysical Phenomena · Physics 2024-02-20 Zhen-Yu Yan , Jun Yang , Xiao-Hong Zhao , Yan-Zhi Meng , Bin-Bin Zhang

For over two decades, gamma-ray burst (GRB) prompt emission spectra were modelled with smoothly-broken power laws (Band function), and a positive and tight correlation between the spectral rest-frame peak energy $E_p$ and the total…

High Energy Astrophysical Phenomena · Physics 2024-09-16 Alessio Mei , Gor Oganesyan , Samanta Macera

The quasi-thermal components found in many Fermi gamma-ray bursts (GRBs) imply that the photosphere emission indeed contributes to the prompt emission of many GRBs. But whether the observed spectra empirically fitted by the Band function or…

High Energy Astrophysical Phenomena · Physics 2019-09-02 Yan-Zhi Meng , Liang-Duan Liu , Jun-Jie Wei , Xue-Feng Wu , Bin-Bin Zhang

A time-resolved spectral analysis for a sample of 22 intense, broad GRB pulses from the BATSE GRB sample is presented. We fit the spectra with the Band function and investigate the correlation between the observed flux (F) and the peak…

Astrophysics of Galaxies · Physics 2015-05-19 R. -J. Lu , S. -J. Hou , En-Wei Liang

Data from four Fermi-detected gamma-ray bursts (GRBs) is used to set limits on spectral dispersion of electromagnetic radiation across the universe. The analysis focuses on photons recorded above 1 GeV for Fermi detected GRB 080916C, GRB…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Robert J. Nemiroff , Ryan Connolly , Justin Holmes , Alexander B. Kostinski

After seven years of science operation, the Fermi mission has brought great advances in the study of Gamma-ray Bursts (GRBs). Over 1600 GRBs have been detected by the Gamma-ray Burst Monitor, and more than 100 of these are also detected by…

High Energy Astrophysical Phenomena · Physics 2015-07-19 Elisabetta Bissaldi , Francesco Longo , Nicola Omodei , Giacomo Vianello , Andreas von Kienlin

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…

We develop a new method for simultaneous timing and spectral studies of Gamma Ray Burst (GRB) prompt emission and apply it to make a pulse-wise description of the prompt emission of GRB 090618, the brightest GRB detected in the Fermi era.…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Rupal Basak , A. R. Rao

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 emission mechanism during the prompt phase in gamma-ray bursts (GRBs) can be investigated through correlations between spectral properties. Here, we revisit the correlation relating the instantaneous flux, $F$, and the photon index…

High Energy Astrophysical Phenomena · Physics 2019-01-16 Felix Ryde , Hoi-Fung Yu , Hüsne Dereli-Bégué , Christoffer Lundman , Asaf Pe'er , Liang Li

We perform a detailed analysis on broad pulses in bright Gamma-ray bursts (GRBs) to understand the evolution of GRB broad pulses. Using the temporal and spectral properties, we test the high latitude emission (HLE) scenario in the decaying…

High Energy Astrophysical Phenomena · Physics 2023-06-14 Donggeun Tak , Z. Lucas Uhm , Judith Racusin , Bing Zhang , Sylvain Guiriec , Daniel Kocevski , Bin-Bin Zhang , Julie McEnery

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

We study the spectral evolution of 13 short duration Gamma Ray Bursts (GRBs) detected by the Gamma Burst Monitor (GBM) on board Fermi. We study spectra resolved in time at the level of 2-512 ms in the 8 keV-35 MeV energy range. We find a…

High Energy Astrophysical Phenomena · Physics 2015-05-19 G. Ghirlanda , G. Ghisellini , L. Nava , D. Burlon

The synchrotron external shock model predicts the evolution of the spectral ($\beta$) and temporal ($\alpha$) indices during the gamma-ray burst (GRB) afterglow for different environmental density profiles, electron spectral indices,…

High Energy Astrophysical Phenomena · Physics 2019-10-15 Donggeun Tak , Nicola Omodei , Z. Lucas Uhm , Judith Racusin , Katsuaki Asano , Julie McEnery

Context: The Crab pulsar is a bright $\gamma$-ray source detected at photon energies up to $\sim$1 TeV. Its phase-averaged and phase-resolved $\gamma$-ray spectra below 10 GeV exhibit exponential cutoffs while those above 10 GeV apparently…

High Energy Astrophysical Phenomena · Physics 2021-05-05 Paul K. H. Yeung

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 explain the results of Yu et al. (2015b) of the novel sharpness angle measurement to a large number of spectra obtained from the Fermi gamma-ray burst monitor. The sharpness angle is compared to the values obtained from various…