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Gamma-ray bursts (GRBs) are extremely powerful explosions that have been traditionally classified into two categories: long bursts (LGRBs) with an observed duration T90 > 2 s, and short bursts (SGRBs) with an observed duration T90 < 2 s,…

High Energy Astrophysical Phenomena · Physics 2024-03-25 Ali M. Hasan , Walid J. Azzam

Gamma-ray bursts (GRBs) are powerful probes of early stars and galaxies, during and potentially even before the era of reionization. Although the number of GRBs identified at z>6 remains small, they provide a unique window on typical…

We have performed a systematic study of Gamma-Ray Bursts (GRBs), which have various values in the peak energy of the ${\nu}F_{\nu}$ spectrum of the prompt emission, $E_{{\rm peak}}$, observed by \textsl{Swift}/BAT and \textsl{Fermi}/GBM,…

High Energy Astrophysical Phenomena · Physics 2020-02-12 Daisuke Katsukura , Takanori Sakamoto , Makoto S. Tashiro , Yukikatsu Terada

Since it is not possible to predict when a Gamma-Ray Burst (GRB) will occur or when Active Galactic Nucleus (AGN) flaring activity starts, follow-up/monitoring ground telescopes must be located as uniformly as possible all over the world in…

High Energy Astrophysical Phenomena · Physics 2015-05-20 T. Sakamoto , C. A. Wallace , D. Donato , N. Gehrels , T. Okajima , T. N. Ukwatta

Luminosity function and event rate of Gamma-Ray Bursts (GRBs) are easily biased by the instrument and selection effects. We select 115 Fermi/GBM GRBs with good spectra fitted by a smoothly broken power-law function. The $\tau$-statistic…

High Energy Astrophysical Phenomena · Physics 2025-07-23 Yang Liu , Zhi-Bin Zhang , Xiao-Fei Dong , Long-Biao Li , Xiu-Yun Du

Abundances of galaxies at redshifts z > 4 are difficult to obtain from damped Ly {\alpha} (DLA) systems in the sightlines of quasars (QSOs) due to the Ly {\alpha} forest blanketing and the low number of high-redshift quasars detected.…

We show that the time variability of a gamma-ray burst (GRB) appears to be correlated with the absolute luminosity of the burst: smooth bursts are intrinsically less luminous. This Cepheid-like relationship can be used to determine the…

Astrophysics · Physics 2007-05-23 E. E. Fenimore , E. Ramirez-Ruiz

We show how the observed gamma ray burst (GRB) optical afterglow (OA) and redshift distributions are changing in time from selection effects. For a subset of {\it Swift} triggered long duration bursts, we show that the mean time taken to…

Astrophysics · Physics 2011-05-09 D. M. Coward

There have now been three supernova-associated gamma-ray bursts (GRBs) at redshift z < 0.17, namely 980425, 030329, and 031203, but the nearby and under-luminous GRBs 980425 and 031203 are distinctly different from the `classical' or…

Astrophysics · Physics 2009-11-11 D. M. Coward

The T\'elescope \`a Action Rapide pour les Objets Transitoires (TAROT-1) has as prime objective the observation of the prompt and delayed emission of cosmic gamma-ray bursts (GRBs). We have performed a search for optical emission from 6…

Astrophysics · Physics 2009-11-07 M Boer , J-L Atteia , M Bringer , B Gendre , A Klotz , R Malina , J-A de Freitas Pacheco , H Pedersen

We summarize our model for long-duration gamma ray bursts (GRBs) that fits the redshift (z) distributions measured with Swift and missions before Swift, and the pre-Swift GRB jet opening-angle distribution inferred from achromatic breaks in…

Astrophysics · Physics 2008-11-26 Truong Le , Charles D. Dermer

Gamma Ray Bursts (GRB) are among the brightest objects in the Universe and hence can be observed up to a very high redshift. Properly calibrated empirical correlations between intensity and spectral correlations of GRBs can be used to…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-22 Meghendra Singh , Darshan Singh , Kanhaiya Lal Pandey , Dinkar Verma , Shashikant Gupta

From the launch of the Fermi Gamma-ray Space Telescope to July 9, 2010, the Gamma-ray Burst Monitor (GBM) has detected 497 probable GRB events. Twenty-two of these satisfy the simultaneous requirements of an estimated burst direction within…

High Energy Astrophysical Phenomena · Physics 2015-05-20 C. W. Akerlof , W. Zheng , S. B. Pandey , T. A. McKay

The 26 long-duration gamma-ray bursts (GRBs) with known redshifts form a distinct cosmological set, selected differently than other cosmological probes such as quasars and galaxies. Since the progenitors are now believed to be connected…

Astrophysics · Physics 2009-11-07 J. S. Bloom

Gamma-ray Bursts (GRBs) are one of the most energetic phenomena in the cosmos, whose study probes physics extremes beyond the reach of laboratories on Earth. Our quest to unravel the origin of these events and understand their underlying…

High Energy Astrophysical Phenomena · Physics 2025-02-25 Michela Negro , Nicoló Cibrario , Eric Burns , Joshua Wood , Adam Goldstein , Tito Dal Canton

While the high-z frontier of star formation rate (SFR) studies has advanced rapidly, direct measurements beyond z ~ 4 remain difficult, as shown by significant disagreements among different results. Gamma-ray bursts, owing to their…

Astrophysics · Physics 2011-02-11 Hasan Yuksel , Matthew D. Kistler , John F. Beacom , Andrew M. Hopkins

Gamma-Ray Bursts (GRBs), being observed at high redshift (z = 9.4), vital to cosmological studies and investigating Population III stars. To tackle these studies, we need correlations among relevant GRB variables with the requirement of…

High Energy Astrophysical Phenomena · Physics 2023-08-16 Maria G. Dainotti , Ritwik Sharma , Aditya Narendra , Delina Levine , Enrico Rinaldi , Agnieszka Pollo , Gopal Bhatta

Gamma-ray Bursts (GRB) were discovered by satellite-based detectors as powerful sources of transient $\gamma$-ray emission. The Fermi satellite detected an increasing number of these events with its dedicated Gamma-ray Burst Monitor (GBM),…

Instrumentation and Methods for Astrophysics · Physics 2021-09-29 G. La Mura , U. Barres de Almeida , R. Conceição , A. De Angelis , F. Longo , M. Pimenta , E. Prandini , E. Ruiz-Velasco , B. Tomé

In this letter, we calculate the redshift distribution of gamma-ray bursts assuming that they trace (i) the globally averaged star formation rate or (ii) the average metallicity in the Universe. While at redshifts 5 and below, both the star…

The exhilerating results from Swift in its first year of operations have opened a new era of exploration of the high energy universe. The surge to higher redshifts of the Gamma-ray bursts now imaged with increased sensitivity establishes…

Astrophysics · Physics 2015-06-24 Jonathan E. Grindlay