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Understanding the origin and diversity of emission processes responsible for Gamma-ray Bursts (GRBs) remains a pressing challenge. While prompt and contemporaneous panchromatic observations have the potential to test predictions of the…

The radiative process responsible for gamma-Ray Burst (GRB) prompt emission has not been identified yet. If dominated by fast-cooling synchrotron radiation, the part of the spectrum immediately below the $\nu F_\nu$ peak energy should…

High Energy Astrophysical Phenomena · Physics 2017-09-20 Gor Oganesyan , Lara Nava , Giancarlo Ghirlanda , Annalisa Celotti

Gamma-ray bursts (GRBs) are the most luminous explosions in the universe, yet the nature and physical properties of their energy sources are far from understood. Very important clues, however, can be inferred by studying the afterglows of…

We present results from extensive broadband follow-up of GRB 210204A over the period of thirty days. We detect optical flares in the afterglow at 7.6 x 10^5 s and 1.1 x 10^6 s after the burst: the most delayed flaring ever detected in a GRB…

The Gamma-Ray Burst (GRB) 021211 detected by the High Energy Transient Explorer (HETE) II had a simple light-curve in the x-ray and gamma-ray energy bands containing one peak and little temporal fluctuation other than the expected Poisson…

Astrophysics · Physics 2009-11-07 Pawan Kumar , Alin Panaitescu

GRB 111209A is the longest ever recorded burst. This burst was detected by Swift and Konus-Wind, and we obtained TOO time from XMM-Newton as well as prompt data from TAROT. We made a common reduction using data from these instruments…

High Energy Astrophysical Phenomena · Physics 2013-08-06 B. Gendre , G. Stratta , J. L. Atteia , S. Basa , M. Boer , D. M. Coward , S. Cutini , V. D'Elia , E. J. Howell , A. Klotz , S. Oates , M. De Pasquale , L. Piro

We present a possible theoretical interpretation of the observed afterglow emission of long gamma-ray burst GRB 080710. While its prompt GRB emission properties are normal, the afterglow light curves in the optical and infrared bands are…

High Energy Astrophysical Phenomena · Physics 2024-01-10 Kaori Obayashi , Ayumu Toriyama , Mayu Murakoshi , Yuri Sato , Shuta J. Tanaka , Takanori Sakamoto , Ryo Yamazaki

Recent rapid localizations of short, hard gamma-ray bursts (GRBs) by the Swift and HETE satellites have led to the observation of the first afterglows and the measurement of the first redshifts from this type of burst. Detection of >100 GeV…

Long-lived high-energy (>100MeV) emission, a common feature of most Fermi-LAT detected gamma-ray burst, is detected up to \sim 10^2 s in the short GRB 090510. We study the origin of this long-lived high-energy emission, using broad-band…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Hao-Ning He , Xue-Feng Wu , Kenji Toma , Xiang-Yu Wang , Peter Meszaros

We aim to investigate the ability of simple spectral models to describe the GRB early afterglow emission. We performed a time resolved spectral analysis of a bright GRB sample detected by the Swift Burst Alert Telescope and promptly…

We report a multi-wavelength analysis of the prompt emission and early afterglow of GRB051111 and discuss its properties in the context of current fireball models. The detection of GRB051111 by the Burst Alert Telescope on-board Swift…

Observing and understanding the origin of the very-high-energy (VHE) spectral component in gamma-ray bursts (GRBs) has been challenging because of the lack of sensitivity in MeV-GeV observations, so far. The majestic GRB 221009A, known as…

Context: GRB 211106A and GRB 211227A are recent gamma-ray bursts (GRBs) with initial X-ray positions suggesting associations with nearby galaxies (z < 0.7). Their prompt emission characteristics indicate GRB 211106A is a short-duration GRB…

We present Ulysses and NEAR data from the detection of the short or intermediate duration (2 s) gamma-ray burst GRB000301C (2000 March 1.41 UT). The gamma-ray burst (GRB) was localised by the Inter Planetary Network (IPN) and RXTE to an…

Gamma-ray bursts (GRBs) are intense bursts of high-energy photons (prompt emissions) caused by relativistic jets. After the emissions, multi-wavelength afterglows, from radio to very-high-energy (VHE) gamma-ray, last for more than a few…

High Energy Astrophysical Phenomena · Physics 2023-01-10 Yuri Sato , Kaori Obayashi , B. Theodre Zhang , Shuta J. Tanaka , Kohta Murase , Yutaka Ohira , Ryo Yamazaki

The TeV observations of GRB~221009A provided us with a unique opportunity to analyze the contemporaneous phase in which both prompt and afterglow emissions are seen simultaneously. To describe this initial phase of Gamma-Ray Burst…

High Energy Astrophysical Phenomena · Physics 2023-12-05 Evgeny Derishev , Tsvi Piran

Our knowledge of the intrinsic properties of short duration Gamma-Ray Bursts has relied, so far, only upon a few cases for which the estimate of the distance and an extended, multiwavelength monitoring of the afterglow have been obtained.…

The prompt GRB emission is thought to arise from electrons accelerated in internal shocks propagating within a highly relativistic outflow. The launch of Fermi offers the prospect of observations with unprecedented sensitivity in…

Astrophysics · Physics 2015-05-13 Z. Bosnjak , F. Daigne , G. Dubus

The mechanism that causes the prompt-emission episode of gamma-ray bursts (GRBs) is still widely debated despite there being thousands of prompt detections. The favoured internal shock model relates this emission to synchrotron radiation.…