An introduction to "Trapped fireshell (halo) of photons and pairs around black-hole horizon: Source for ultra-high-energy particles"

by Prof. She-Sheng Xue (ICRANet, Physics Department, Sapienza University of Rome)

Thursday 10 Dec 2026, 11:00 → 12:00 Europe/Rome

We study the Compton-rocket effect of strong radiation force accelerating electrons in an opaque fireshell (or fire spot) of dense photons and electron-positron pairs, whose temperature is spatially inhomogeneous and exceeds the electron mass. We find the possibility of the charged-particle acceleration and the avalanche runaway process, leading to a non-trivial probability of ultra-high-energy (UHE) electrons and protons, which subsequently produce very-high-energy (VHE) photons and neutrinos. In a simplified one-dimensional model, we qualitatively show such peculiar dynamics using the fireball, Gamma-Ray Burst central engine, whose inner part inflows and forms a gravitationally trapped fireshell (halo) around the horizon of a black hole. The fireshell is metastable, cooling via UHE particle emissions and blackbody radiation. We calculate the UHE particle luminosity varying in time, and discuss the peculiar features of such produced UHE particles, which lead to VHE particles, in connection with possible numerical simulations, observations and experiments.

JHEAP, August 2026, 100652 Vol. 54 https://www.sciencedirect.com/science/article/pii/S2214404826001035?via%3Dihub

Zoom link: https://icranet-org.zoom.us/meeting/register/4cjhcaTFSluMAlYCTgLagg

She-Sheng Xue, a faculty member at ICRANet. In 1986, received a PhD in theoretical physics at IHEP and the T.D. Lee Fellowship at ITP,  CAS, Beijing. Experience: University of Edinburgh, UK; Brookhaven National Laboratory, USA; INFN and Sapienza University of Rome, Italy. Fields: Theoretical particle physics, cosmology and high-energy astrophysics. Publications: https://inspirehep.net/authors/982993?ui-citation-summary=true