Nature of the ultrarelativistic prompt emission phase of GRB 190114C

We address the physical origin of the ultrarelativistic prompt emission (UPE) phase of GRB 1901140 observed in the interval t(rf) = 1.9-3.99 s, by the Fermi-GBM in 10 keV-10 MeV energy band. Thanks to the high signal-to-noise ratio of Fermi-GBM data, a time-resolved spectral analysis has evidenced a sequence of similar blackbody plus cutoff power-law spectra (BB + CPL), on ever decreasing time intervals during the entire UPE phase. We assume that during the UPE phase, the inner engine of the GRB, composed of a Kerr black hole (BH) and a uniform test magnetic field B-0, aligned with the BH rotation axis, operates in an overcritical field vertical bar E vertical bar >= E-c, where E-c = m(e)(2)c(3)/(e (h) over bar), being m(e) and -e the mass and charge of the electron. We infer an e(+)e(-) pair electromagnetic plasma in presence of a baryon load, a PEMB pulse, originating from a vacuum polarization quantum process in the inner engine. This initially optically thick plasma self-accelerates, giving rise at the transparency radius to the MeV radiation observed by Fermi-GBM. At times t(rf) > 3.99 s, the electric field becomes undercritical, vertical bar E vertical bar < E-c, and the inner engine, as previously demonstrated, operates in the classical electrodynamics regime and generate the GeV emission. During both the quantum and the classical electrodynamics processes, we determine the time varying mass and spin of the Kerr BH in the inner engine, fulfilling the Christodoulou-Hawking-Ruffini mass-energy formula of a Kerr BH. For the first time, we quantitatively show how the inner engine, by extracting the rotational energy of the Kerr BH, produces a series of PEMB pulses. We follow the quantum vacuum polarization process in sequences with decreasing time bins. We compute the Lorentz factors, the baryon loads and the radii at transparency, as well as the value of the magnetic field, B-0, assumed to be constant in each sequence. The fundamental hierarchical structure, linking the quantum electrodynamics regime to the classical electrodynamics regime, is characterized by the emission of blackholic quanta with a timescale tau similar to 10(-9) s, and energy epsilon similar to 10(45) erg.

Automated summary

The study investigates the physical origin of the ultrarelativistic prompt emission (UPE) phase of GRB 1901140, revealing the presence of a Kerr black hole and a uniform test magnetic field in the inner engine, which generates PEMB pulses through a quantum process. The time-varying mass and spin of the Kerr BH in the inner engine lead to the production of a series of PEMB pulses.