Hadronic supercriticality in spherically expanding sources: application to GRB prompt emission

Relativistic hadronic plasmas can become, under certain conditions, supercritical, abruptly and efficiently releasing the energy stored in protons through photon outbursts. Past studies have tried to relate the features of such hadronic supercriticalities (HSCs) to the phenomenology of gamma-ray burst (GRB) prompt emission. In this work we investigate, for the first time, HSC in adiabatically expanding sources. We examine the conditions required to trigger HSC, study the role of expansion velocity, and discuss our results in relation to GRB prompt emission. We find multipulse light curves from slowly expanding regions (less than or similar to 0.01c) that are a manifestation of the natural HSC quasi-periodicity, while single-pulse light curves with a fast rise and slow decay are found for higher velocities. The formation of the photon spectrum is governed by an in-source electromagnetic cascade. The peak photon energy is approximately 1 center dot Gamma/ 100 1+ z 3 MeV for maximum proton energies (1 - 10) center dot Gamma/ 100 1+ z 3 PeV, while the peak.-ray luminosities are in the range (1049 - 1052) center dot ( Gamma/ 100)4 erg s(-1). HSC bursts peaking in the MeV energy band are also copious neutrino emitters with peak energies Gamma/ 10 center dot Gamma/ 100 1+ z 3 TeV and an all-flavour neutrino fluence similar to 10 per cent of the.-ray one. The hypothesis that long-duration GRBs are powered by HSCs could be applied therefore only to the most luminous GRBs observed assuming bulk Lorentz factors Gamma <= 100.

Automated summary

Relativistic hadronic plasmas can become supercritical, releasing energy through photon outbursts. This study investigates hadronic supercriticalities in adiabatically expanding sources, examining the trigger conditions and the role of expansion velocity. The results suggest a connection between these supercriticalities and gamma-ray burst prompt emission, providing insights into the formation of light curves and photon spectra.