scholarly journals In Vacuo Dispersion-Like Spectral Lags in Gamma-Ray Bursts

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 541
Author(s):  
Giovanni Amelino-Camelia ◽  
Giacomo D’Amico ◽  
Fabrizio Fiore ◽  
Simonetta Puccetti ◽  
Michele Ronco
Keyword(s):  
Statistical Analysis ◽  
Linear Correlation ◽  
Gamma Ray ◽  
Statistical Evidence ◽  
Gamma Ray Bursts ◽  
Quantum Geometry

Some recent studies exposed preliminary but rather intriguing statistical evidence of in vacuo dispersion-like spectral lags for gamma-ray bursts (GRBs), a linear correlation between time of observation and energy of GRB particles, which is expected in some models of quantum geometry. Those results focused on testing in vacuo dispersion for the most energetic GRB particles, and in particular only included photons with energy at emission greater than 40 GeV. We here extend the window of the statistical analysis down to 5 GeV and find results that are consistent with what had been previously noticed at higher energies.

scholarly journals Optical Afterglows as Probes for the Central Engine and Fireball of Gamma-Ray Bursts

2012 ◽  
Vol 8 (S290) ◽  
pp. 263-264
Author(s):  
Liang Li ◽  
En-Wei Liang ◽  
He Gao ◽  
Bing Zhang
Keyword(s):  
Statistical Analysis ◽  
Gamma Rays ◽  
Density Profile ◽  
Gamma Ray ◽  
Ambient Medium ◽  
Gamma Ray Bursts ◽  
Prompt Gamma ◽  
Medium Density ◽  
Central Engine ◽  
Prompt Emission

AbstractWell-sampled optical lightcurves of 146 gamma-ray bursts (GRBs) are compiled from literature. We identify possible emission components based on our empirical fits and present statistical analysis for these components. We find that the flares are related to prompt emission, suggesting that they could have the same origin in different episodes. The shallow decay segment is not correlated with prompt gamma-rays. It likely signals a long-lasting injected wind from GRB central engines. Early after onset peak is closely related with prompt emission. The ambient medium density profile is likely n ∝ r−1. No correlation between the late re-brightening bump and prompt gamma-rays or the onset bump is found. They may be from another jet component.

Precursors of short gamma-ray bursts detected by the INTEGRAL observatory

2018 ◽  
Vol 27 (10) ◽  
pp. 1844013 ◽  
Author(s):  
Pavel Minaev ◽  
Alexei Pozanenko ◽  
Sergei Molkov
Keyword(s):  
Statistical Analysis ◽  
Light Curve ◽  
Relative Intensity ◽  
Gamma Ray ◽  
Convincing Evidence ◽  
Gamma Ray Bursts ◽  
Light Curves ◽  
Upper Limits ◽  
Short Grbs

We have analyzed the light curves of 527 short gamma-ray bursts (GRBs) registered by the SPI-ACS, SPI and IBIS/ISGRI experiments of INTEGRAL observatory totally to search for precursors. Both the light curves of each 527 individual burst and the averaged light curve of 372 brightest SPI-ACS bursts have been analyzed. In a few cases, we have found and investigated precursor candidates using SPI-ACS, SPI and IBIS/ISGRI of INTEGRAL, GBM and LAT of Fermi data. No convincing evidence for the existence of precursors of short GRBs has been found. A statistical analysis of the averaged light curve for the sample of brightest short bursts has revealed no regular precursor. Upper limits for the relative intensity of precursors have been estimated. We show that the fraction of short GRBs with precursors is less than 0.4% of all short bursts, detected by INTEGRAL.

Statistical evidence for a galactic origin of gamma-ray bursts

Nature ◽  
1991 ◽  
Vol 351 (6324) ◽  
pp. 296-298 ◽  
Author(s):  
J. L. Atteia ◽  
C. Barat ◽  
E. Jourdain ◽  
M. Niel ◽  
G. Vedrenne ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Statistical Evidence ◽  
Gamma Ray Bursts

scholarly journals Statistical Evidence for Three Classes of Gamma‐Ray Bursts

2007 ◽  
Vol 667 (2) ◽  
pp. 1017-1023 ◽  
Author(s):  
Tanuka Chattopadhyay ◽  
Ranjeev Misra ◽  
Asis Kumar Chattopadhyay ◽  
Malay Naskar
Keyword(s):  
Gamma Ray ◽  
Statistical Evidence ◽  
Gamma Ray Bursts

Investigation of gamma-ray bursts with known redshifts: Statistical analysis of parameters

2009 ◽  
Vol 35 (1) ◽  
pp. 7-24 ◽  
Author(s):  
D. A. Badjin ◽  
G. M. Beskin ◽  
G. Greco
Keyword(s):  
Statistical Analysis ◽  
Gamma Ray ◽  
Gamma Ray Bursts

scholarly journals Cosmology using long gamma-ray bursts: statistical analysis of errors in calibrated data

2019 ◽  
Vol 19 (2) ◽  
pp. 028
Author(s):  
Meghendra Singh ◽  
Shashikant Gupta ◽  
Amit Sharma ◽  
Satendra Sharma
Keyword(s):  
Statistical Analysis ◽  
Gamma Ray ◽  
Gamma Ray Bursts

A statistical analysis of gamma-ray bursts based on the beaming model

1996 ◽  
Vol 20 (4) ◽  
pp. 402-408 ◽  
Author(s):  
Hai-hong Che ◽  
Li-ming Song ◽  
Wen-fei Yu ◽  
Fang-jun Lu
Keyword(s):  
Statistical Analysis ◽  
Gamma Ray ◽  
Gamma Ray Bursts

scholarly journals GRB Duration Distribution Considering the Position of the Fermi

10.14311/1510 ◽  
2012 ◽  
Vol 52 (1) ◽  
Author(s):  
D. Szécsi ◽  
Z. Bagoly ◽  
I. Horváth ◽  
L. G. Balázs ◽  
P. Veres ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Side Effect ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
New Technique ◽  
Filtering Method ◽  
Duration Distribution ◽  
Statistical Surveys ◽  
A New Technique

The Fermi satellite has a particular motion during its flight which enables it to catch the gamma-ray bursts mostly well. The side-effect of this favourable feature is that the lightcurves of the GBM detectors are stressed by rapidly and extremely varying background. Before this data is processed, it needs to be separated from the background. The commonly used methods [3,7] were useless for most cases of Fermi, so we developed a new technique based on the motion and orientation of the satellite. The background-free lightcurve can be used to perform statistical surveys, hence we showed the efficiency of our background-filtering method presenting a statistical analysis known from the literature.

scholarly journals CORRELATION BETWEEN HARDNESS RATIO AND DURATION OF FERMI GAMMA-RAY BURSTS

2013 ◽  
Vol 23 ◽  
pp. 298-300
Author(s):  
FU-WEN ZHANG
Keyword(s):  
Statistical Analysis ◽  
Power Law ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Shape ◽  
Energy Bands ◽  
Hardness Ratio

Using the latest gamma-ray bursts (GRB) observed by Fermi-GBM, we perform a statistical analysis of the relation between hardness ratio (HR) and duration (ΔT) of GRBs, and find that HR and ΔT are still anti-correlated. we also find that this correlation strongly depends upon the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR – ΔT correlation is not evident for Swift-BAT GRB sample as well as other GRB sample detected by instruments with a narrower/softer energy bandpass such as HETE-2.

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