GeV–TeV Emission from GRBs: Insights from Recent Observations

by Dr Tsvi Piran (Hebrew University)

Thursday 5 Jun 2025, 11:30 → 12:30 Europe/Rome

Sala Jappelli (Osservatorio astronomico di Padova)

Recent observations by MAGIC, HESS, and LHASSO have detected several gamma-ray bursts (GRBs) as GeV–TeV sources. These findings offer a fresh perspective on the longstanding GRB puzzle. In this talk, I will review these high-energy detections, with particular focus on GRB 190114A and the exceptionally bright GRB 221009A (the “BOAT”). A key insight emerging from these observations is that the extremely high-energy photons do not originate during the prompt emission phase. Rather, they are produced during the very early afterglow stage, likely through synchrotron self-Compton (SSC) processes. This realization compels us to revisit conventional models of particle acceleration in relativistic shocks. At the same time, these observations provide a rare window into an otherwise unexplored stage of GRB evolution—the initial interaction of the blast wave with the ambient medium. Additionally, the detection of such high-energy photons carries intriguing implications for constraints on quantum gravity theories. Finally, I will touch on a novel class of gravitational wave signals that may be associated with GRBs, offering new possibilities for multi-messenger astronomy.

 

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https://unipd.zoom.us/j/85273198731?pwd=V1ZiNE9ZWUN4ZTdIUzJsTFo0Z3U2Zz09
Meeting ID: 852 7319 8731
Passcode: 208186