Implication of GRB 221009A: Can TeV Emission Come from the GRB Prompt Phase?

TL;DR

This paper suggests that the very-high-energy gamma-ray emission from GRB 221009A, including energies above 10 TeV, can originate from internal hadronic processes within the GRB, supporting a magnetically dominated ejecta and the BZ mechanism.

Contribution

It demonstrates that VHE gamma-ray emission from GRB 221009A can be explained by internal hadronic dissipation without exotic processes, favoring a Poynting-flux-dominated ejecta and the BZ central engine.

Findings

VHE emission above 10 TeV can originate from internal hadronic processes.

Supports a magnetically dominated GRB ejecta model.

Favors the Blandford & Znajek mechanism as the central engine.

Abstract

Recently, the B.O.A.T. ("brightest of all time") gamma-ray burst, dubbed GRB 221009A, was detected by various instruments. Unprecedentedly, the GRB presented very-high-energy (VHE, energy above 0.1 TeV) gamma-ray emission with energy extending above 10 TeV, as reported by the Large High Altitude Air Shower Observatory (LHAASO). We here demonstrate that the VHE and especially >10 TeV emission may originate from the internal hadronic dissipation of the GRB, without the need of invoking any exotic processes as suggested by some previous studies. We also discuss the constraints on the properties of the GRB ejecta from multiwavelength and multi-messenger observations, which favors a magnetically dominated GRB ejecta. The suggested Poynting-flux-dominated GRB ejecta in this work supports the Blandford & Znajek (BZ) mechanism as the possible central engine model of GRB.