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Despite the great variation in the light curves of Gamma Ray Burst (GRB) prompt emission, their spectral energy distribution is generally curved and broadly peaked. In particular, their spectral evolution is well described by the…

High Energy Astrophysical Phenomena · Physics 2015-05-27 F. Massaro , J. E. Grindlay

The properties of the spectral evolution during the prompt emission phase of gamma-ray bursts (GRBs), which are closely related to the radiation mechanism (synchrotron or photosphere), are still a subject of debate. Two spectral evolution…

High Energy Astrophysical Phenomena · Physics 2026-04-21 Liang Li

A characteristic energy of individual gamma-ray burst (GRB) spectra can in most cases be determined from the peak energy of the energy density spectra ($\nu{\cal F}_{\nu}$), called '$E_{\rm peak}$'. Distributions of $E_{\rm peak}$ have been…

High Energy Astrophysical Phenomena · Physics 2016-04-20 Robert Preece , Adam Goldstein , Narayana Bhat , Matthew Stanbro , Jon Hakkila , Dylan Blalock

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…

High Energy Astrophysical Phenomena · Physics 2012-08-23 Rui-Jing Lu , Jun-Jie Wei , En-Wei Liang , Bin-Bin Zhang , Hou-Jun Lü , Lian-Zhong , , Wei-Hua Lei , Bing Zhang

As a result of spherical kinematics, temporal evolution of received gamma-ray emission should demonstrate signatures of curvature from the emitting shell. Specifically, the shape of the pulse decay must bear a strict dependence on the…

Astrophysics · Physics 2009-11-06 Alicia M. Soderberg , Edward E. Fenimore

The spectral evolution and spectral lag behavior of 92 bright pulses from 84 gamma-ray bursts (GRBs) observed by the Fermi GBM telescope are studied. These pulses can be classified into hard-to-soft pulses (H2S, 64/92),…

High Energy Astrophysical Phenomena · Physics 2018-10-17 Rui-Jing Lu , Yun-Feng Liang , Da-Bin Lin , Jing Lv , Xiang-Gao Wang , Hou-Jun Lv , Hong-Bang Liu , En-Wei Liang , Bing 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

Gamma-ray bursts (GRBs) are highly variable and exhibit strong spectral evolution. In particular, the emission properties vary from pulse to pulse in multipulse bursts. Here we present a time-resolved Bayesian spectral analysis of a…

High Energy Astrophysical Phenomena · Physics 2021-12-20 Liang Li , Felix Ryde , Asaf Pe'er , Hoi-Fung Yu , Zeynep Acuner

We investigate spectral evolution in 37 bright, long gamma-ray bursts observed with the BATSE Spectroscopy Detectors. High resolution spectra are characterized by the energy of the peak of \nfn~and the evolution of this quantity is examined…

The prompt emission phase of gamma-ray bursts (GRBs) exhibits two distinct patterns of the peak-energy ($E_p$) evolution, i.e., time-resolved spectral analyses of $\nu F_{\nu}$ spectra of broad pulses reveal (1) "hard-to-soft" and (2)…

High Energy Astrophysical Phenomena · Physics 2018-12-26 Z. Lucas Uhm , Bing Zhang , Judith Racusin

A study of a set of well-isolated pulses in Long and Intermediate gamma ray burst light curves indicates that simple pulse models having smooth and monotonic pulse rise and decay regions are inadequate. Examining the residuals of fits of…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Jon Hakkila , Robert D. Preece

The prompt emission mechanism of gamma-ray bursts (GRBs) is still unclear, and the time-resolved spectral analysis of GRBs is a powerful tool for studying their underlying physical processes. We performed a detailed time-resolved spectral…

High Energy Astrophysical Phenomena · Physics 2024-01-29 Wan-Kai Wang , Wei Xie , Zhi-Fu Gao , Shuo Xiao , Ai-Jun Dong , Bin Zhang , Qi-Jun Zhi

We have analyzed the evolution of the spectral hardness parameter Epk as a function of fluence in gamma-ray bursts. We fit 41 pulses within 26 bursts with the trend reported by Liang & Kargatis (1996) which found that Epk decays…

In this paper we have analyzed the temporal and spectral behavior of 52 Fast Rise and Exponential Decay (FRED) pulses in 48 long-duration gamma-ray bursts (GRBs) observed by the CGRO/BATSE, using a pulse model with two shape parameters and…

High Energy Astrophysical Phenomena · Physics 2014-11-21 Z. Y. Peng , Y. Yin , X. W. Bi , X. H. Zhao , L. M. Fang , Y. Y. Bao , L. Ma

For the first time, the consequences of combining two well-established empirical relations, describing different aspects of the spectral evolution of observed gamma-ray burst (GRB) pulses, are explored. These empirical relations are: i) the…

Astrophysics · Physics 2009-10-31 Felix Ryde , Roland Svensson

We describe the strong spectral evolution that occurs during a gamma-ray burst pulse and the means by which it can be analyzed. Based on observed empirical correlations, an analytical model is constructed which is used to describe the pulse…

Astrophysics · Physics 2009-11-10 Felix Ryde

Isolated Swift gamma-ray burst (GRB) pulses, like their higher-energy BATSE counterparts, emit the bulk of their pulsed emission as a hard-to-soft component that can be fitted by the Norris et al. (2005) empirical pulse model. This signal…

High Energy Astrophysical Phenomena · Physics 2016-01-20 Jon Hakkila , Amy Lien , Takanori Sakamoto , David Morris , James E. Neff , Timothy W. Giblin

The spectral evolution characteristics of the prompt emission in gamma-ray bursts (GRBs) have been extensively studied, but detailed investigations of spectral evolution in a GRB flare remain lacking. In this work, we present the first…

We report evidence that the asymptotic low-energy power law slope alpha (below the spectral break) of BATSE gamma-ray burst photon spectra evolves with time rather than remaining constant. We find a high degree of positive correlation…

We analyze the spectral evolution of 62 bright Fermi gamma-ray bursts with large enough signal to noise to allow for time resolved spectral analysis. We develop a new algorithm to test for single-pulse morphology that is insensitive to the…

High Energy Astrophysical Phenomena · Physics 2024-08-28 Ian Busby , Davide Lazzati
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