Summary:

Gamma-ray bursts (GRBs) are one of the most energetic explosions known in the Universe and are also known to have the most relativistic jets, with initial expansion Lorentz factors of hundreds. Depending on the prompt duration and hardness ratio, GRBs are broadly classified as hard-short (<2 s) and soft-long (>2 s) GRBs. The prompt phase is followed by the afterglow, observed for several days at all wavelengths, from radio to TeV including optical and X-ray bands. The origin of the plateau phase observed in the early X-ray light curve of GRBs has been debated since its discovery in 2005. In our recent paper, we show that observed plateau phase can be explained within the classical GRB model by considering an expanding stellar shell with initial jet Lorentz factors of tens. In this talk, after giving a brief introduction about the topic, I will present the key findings of the paper and I will list all the supporting evidences for this result.

For more information please contact Piron F.