A POSSIBLE EXPLANATION OF ENERGY DEPENDENCE OF GRB PULSE WIDTH

2013 ◽  
Vol 23 ◽  
pp. 301-303
Author(s):  
XIAO-HONG ZHAO ◽  
ZHAO-YANG PENG
Keyword(s):  
Energy Dependence ◽  
Power Law ◽  
Pulse Width ◽  
Gamma Ray ◽  
Decay Phase ◽  
Band Spectrum ◽  
Curvature Effect ◽  
Gamma Ray Burst ◽  
Energy Dependent ◽  
Single Power

Previous studies have found that the width of gamma-ray burst (GRB) pulse is energy dependent1-2 and its origin keeps unknown. Here we find combining the curvature effect and the intrinsic Band spectrum could naturally result in the energy dependence of GRB pulse width. Our result suggests that the GRB decay phase is indeed related to the so-called curvature effect. A natural expectation of our study is for bursts with single power law, not Band spectrum, pulse width will not be energy dependent in our consideration.

scholarly journals ENERGY-DEPENDENT GAMMA-RAY BURST PULSE WIDTH DUE TO THE CURVATURE EFFECT AND INTRINSIC BAND SPECTRUM

2012 ◽  
Vol 752 (2) ◽  
pp. 132 ◽  
Author(s):  
Z. Y. Peng ◽  
X. H. Zhao ◽  
Y. Yin ◽  
Y. Y. Bao ◽  
L. Ma
Keyword(s):  
Pulse Width ◽  
Gamma Ray ◽  
Band Spectrum ◽  
Curvature Effect ◽  
Gamma Ray Burst ◽  
Burst Pulse ◽  
Energy Dependent

scholarly journals A test of the power-law relationship between gamma-ray burst pulse-width ratio and energy expected in fireballs and uniform jets

2006 ◽  
Vol 368 (3) ◽  
pp. 1351-1358 ◽  
Author(s):  
Z.-Y. Peng ◽  
Y.-P. Qin ◽  
B.-B. Zhang ◽  
R.-J. Lu ◽  
L.-W. Jia ◽  
...  
Keyword(s):  
Power Law ◽  
Pulse Width ◽  
Gamma Ray ◽  
Width Ratio ◽  
Gamma Ray Burst ◽  
Burst Pulse

scholarly journals Evidence of X-Ray Plateaus Driven by the Magnetar Spindown Winds in Gamma-Ray Burst Afterglows

2021 ◽  
Vol 922 (2) ◽  
pp. 102
Author(s):  
Shu-Jin Hou ◽  
Shuang Du ◽  
Tong Liu ◽  
Hui-Jun Mu ◽  
Ren-Xin Xu
Keyword(s):  
Gamma Ray ◽  
Normal Component ◽  
Gamma Ray Bursts ◽  
Cutting Edge ◽  
Decay Phase ◽  
Gamma Ray Burst ◽  
X Ray ◽  
Central Engine

Abstract The central engine of gamma-ray bursts (GRBs) remains an open and cutting-edge topic in the era of multimessenger astrophysics. X-ray plateaus appear in some GRB afterglows, which are widely considered to originate from the spindown of magnetars. According to the stable magnetar scenario of GRBs, an X-ray plateau and a decay phase ∼t −2 should appear in X-ray afterglows. Meanwhile, the “normal” X-ray afterglow is produced by the external shock from a GRB fireball. We analyze the Neil Gehrels Swift GRB data, then find three gold samples that have an X-ray plateau and a decay phase ∼t −2 superimposed on the jet-driven normal component. Based on these features of the lightcurves, we argue that the magnetars should be the central engines of these three GRBs. Future joint multimessenger observations might further test this possibility, which can then be beneficial to constrain GRB physics.

scholarly journals Spectral properties of gamma-ray bursts observed by the Suzaku wide-band all-sky monitor

2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Norisuke Ohmori ◽  
Kazutaka Yamaoka ◽  
Makoto Yamauchi ◽  
Yuji Urata ◽  
Masanori Ohno ◽  
...  
Keyword(s):  
Short Duration ◽  
Power Law ◽  
Spectral Properties ◽  
Gamma Ray ◽  
Wide Band ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
Sky Monitor ◽  
S Peak ◽  
Single Power

Abstract We have systematically studied the spectral properties of 302 localized gamma-ray bursts (GRBs) observed by the Suzaku wide-band all-sky monitor (WAM) from 2005 August to 2010 December. The energy spectra in the 100–5000 keV range integrated over the entire emission and the 1 s peak were fitted by three models: a single power law, a power law with an exponential cutoff (CPL), and the GRB Band function (GRB). Most of the burst spectra were well fitted by a single power law. The average photon index α was −2.11 and −1.73 for long and short bursts, respectively. For the CPL and GRB models, the low-energy and high-energy photon indices (α and β) for the entire emission spectra were consistent with previous measurements. The averages of the α and β were −0.90 and −2.65 for long-duration GRBs, while the average α was −0.55 and the β was not well constrained for short-duration GRBs. However, the average peak energy Epeak was 645 and 1286 keV for long- and short-duration GRBs respectively, which are higher than previous Fermi/GBM measurements (285 keV and 736 keV). The α and Epeak of the 1 s peak spectra were larger, i.e., the spectra were harder, than the total fluence spectra. Spectral simulations based on Fermi-GBM results suggest that the higher Epeaks measured by the Suzaku WAM could be due to detector selection bias, mainly caused by the limited energy range above 100 keV.

scholarly journals THEEpEVOLUTIONARY SLOPE WITHIN THE DECAY PHASE OF “FAST RISE AND EXPONENTIAL DECAY” GAMMA-RAY BURST PULSES

2009 ◽  
Vol 698 (1) ◽  
pp. 417-427 ◽  
Author(s):  
Z. Y. Peng ◽  
L. Ma ◽  
X. H. Zhao ◽  
Y. Yin ◽  
L. M. Fang ◽  
...  
Keyword(s):  
Exponential Decay ◽  
Gamma Ray ◽  
Decay Phase ◽  
Gamma Ray Burst ◽  
Fast Rise ◽  
Decay Gamma

scholarly journals Probing the Structure of Gamma‐Ray Burst Jets with the Steep Decay Phase of their Early X‐Ray Afterglows

2007 ◽  
Vol 663 (2) ◽  
pp. 1118-1124 ◽  
Author(s):  
Kentaro Takami ◽  
Ryo Yamazaki ◽  
Takanori Sakamoto ◽  
Goro Sato
Keyword(s):  
Gamma Ray ◽  
Decay Phase ◽  
Gamma Ray Burst ◽  
X Ray ◽  
Steep Decay

scholarly journals GRB 190114C: from prompt to afterglow?

2019 ◽  
Vol 626 ◽  
pp. A12 ◽  
Author(s):  
M. E. Ravasio ◽  
G. Oganesyan ◽  
O. S. Salafia ◽  
G. Ghirlanda ◽  
G. Ghisellini ◽  
...  
Keyword(s):  
Energy Range ◽  
Power Law ◽  
Gamma Ray ◽  
Spectral Energy Distribution ◽  
Onset Time ◽  
Lorentz Factor ◽  
Spectral Energy ◽  
Large Area ◽  
Spectral Evolution ◽  
Gamma Ray Burst

GRB 190114C is the first gamma-ray burst detected at very high energies (VHE, i.e., > 300 GeV) by the MAGIC Cherenkov telescope. The analysis of the emission detected by the Fermi satellite at lower energies, in the 10 keV–100 GeV energy range, up to ∼50 s (i.e., before the MAGIC detection) can hold valuable information. We analyze the spectral evolution of the emission of GRB 190114C as detected by the Fermi Gamma-Ray Burst Monitor (GBM) in the 10 keV–40 MeV energy range up to ∼60 s. The first 4 s of the burst feature a typical prompt emission spectrum, which can be fit by a smoothly broken power-law function with typical parameters. Starting on ∼4 s post-trigger, we find an additional nonthermal component that can be fit by a power law. This component rises and decays quickly. The 10 keV–40 MeV flux of the power-law component peaks at ∼6 s; it reaches a value of 1.7 × 10−5 erg cm−2 s−1. The time of the peak coincides with the emission peak detected by the Large Area Telescope (LAT) on board Fermi. The power-law spectral slope that we find in the GBM data is remarkably similar to that of the LAT spectrum, and the GBM+LAT spectral energy distribution seems to be consistent with a single component. This suggests that the LAT emission and the power-law component that we find in the GBM data belong to the same emission component, which we interpret as due to the afterglow of the burst. The onset time allows us to estimate that the initial jet bulk Lorentz factor Γ0 is about 500, depending on the assumed circum-burst density.

scholarly journals A Bayesian Fermi-GBM short GRB spectral catalogue

2019 ◽  
Vol 490 (1) ◽  
pp. 927-946 ◽  
Author(s):  
J Michael Burgess ◽  
Jochen Greiner ◽  
Damien Bégué ◽  
Franceso Berlato
Keyword(s):  
Light Curve ◽  
Gravitational Wave ◽  
Power Law ◽  
Gamma Ray ◽  
Posterior Distributions ◽  
Time Resolved ◽  
Gamma Ray Burst ◽  
Posterior Predictive Checks ◽  
Peak Flux ◽  
Reduced Data

ABSTRACT Inspired by the confirmed detection of a short gamma-ray burst (GRB) in association with a gravitational wave signal, we present the first Bayesian Fermi-Gamma-ray Burst Monitor (GBM) short GRB spectral catalogue. Both peak flux and time-resolved spectral results are presented. Data are analysed with the proper Poisson likelihood allowing us to provide statistically reliable results even for spectra with few counts. All fits are validated with posterior predictive checks. We find that nearly all spectra can be modelled with a cut-off power law. Additionally, we release the full posterior distributions and reduced data from our sample. Following our previous study, we introduce three variability classes based on the observed light-curve structure.

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