Origin of M87’s VHE gamma‑ray emission

Ascertain the physical origin of the very high‑energy gamma‑ray emission from M87 across both flaring and quiescent states by determining the dominant emission mechanism (e.g., leptonic versus hadronic processes) and the emitting region (e.g., black‑hole magnetosphere, inner jet, or downstream knots).

Background

M87 has shown multiple VHE gamma‑ray flares (2005, 2008, 2010) and a new flare in 2018, yet consistent, multi‑epoch multi‑wavelength observations and modeling have not yielded a definitive physical origin for the VHE emission.

The paper presents contemporaneous VHE detections and compares them to historical flares but concludes that the underlying mechanism and location remain unresolved despite prior campaigns.