A review of early optical GRB features including prompt emission, reverse shocks, and afterglow onset, highlighting robotic telescopes' role in constraining jet Lorentz factors and magnetization.
REM observations of GRB 060418 and GRB 060607A: the onset of the afterglow and the initial fireball Lorentz factor determination
2 Pith papers cite this work. Polarity classification is still indexing.
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abstract
Gamma-ray burst (GRB) emission is believed to originate in highly relativistic fireballs. Currently, only lower limits were securely set to the initial fireball Lorentz factor Gamma_0. We aim to provide a direct measure of Gamma_0. The early-time afterglow light curve carries information about Gamma_0, which determines the time of the afterglow peak. We have obtained early observations of the near-infrared afterglows of GRB 060418 and GRB 060607A with the REM robotic telescope. For both events, the afterglow peak could be clearly singled out, allowing a firm determination of the fireball Lorentz of Gamma_0 ~ 400, fully confirming the highly relativistic nature of GRB fireballs. The deceleration radius was inferred to be R_dec ~ 10^17 cm. This is much larger than the internal shocks radius (believed to power the prompt emission), thus providing further evidence for a different origin of the prompt and afterglow stages of the GRB.
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astro-ph.HE 2years
2026 2verdicts
UNVERDICTED 2representative citing papers
GRB 250424A afterglow shows simultaneous shallow decay in X-ray and optical bands modeled as continuous energy injection (q≈0.34) into a forward shock in constant-density medium, with E_K,iso ≈5.5×10^52 erg and no clear supernova component.
citing papers explorer
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Early Optical Follow-up of Gamma-Ray Bursts: The Critical Role of Robotic Telescopes
A review of early optical GRB features including prompt emission, reverse shocks, and afterglow onset, highlighting robotic telescopes' role in constraining jet Lorentz factors and magnetization.
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GRB 250424A: A Case Study of Energy Injection with Multiwavelength Observations
GRB 250424A afterglow shows simultaneous shallow decay in X-ray and optical bands modeled as continuous energy injection (q≈0.34) into a forward shock in constant-density medium, with E_K,iso ≈5.5×10^52 erg and no clear supernova component.