In:
The Astrophysical Journal, American Astronomical Society, Vol. 941, No. 1 ( 2022-12-01), p. 82-
Kurzfassung:
The emission region of γ -ray bursts (GRBs) is poorly constrained. The uncertainty on the size of the dissipation site spans over 4 orders of magnitude (10 12 –10 17 cm) depending on the unknown energy composition of the GRB jets. The joint multiband analysis from soft X-rays to high energies (up to ∼1 GeV) of one of the most energetic and distant GRBs, GRB 220101A ( z = 4.618), allows us to make an accurate distinction between prompt and early afterglow emissions. The enormous amount of energy released by GRB 220101A ( E iso ≈ 3 × 10 54 erg) and the spectral cutoff at E cutoff = 85 − 26 + 16 MeV observed in the prompt emission spectrum constrain the parameter space of the GRB dissipation site. We put stringent constraints on the prompt emission site, requiring 700 〈 Γ 0 〈 1160 and R γ ∼ 4.5 × 10 13 cm. Our findings further highlight the difficulty of finding a simple self-consistent picture in the electron–synchrotron scenario, favoring instead a proton–synchrotron model, which is also consistent with the observed spectral shape. Deeper measurements of the time variability of GRBs, together with accurate high-energy observations (MeV–GeV), would unveil the nature of the prompt emission.
Materialart:
Online-Ressource
ISSN:
0004-637X
,
1538-4357
DOI:
10.3847/1538-4357/aca091
Sprache:
Unbekannt
Verlag:
American Astronomical Society
Publikationsdatum:
2022
ZDB Id:
2207648-7
ZDB Id:
1473835-1
SSG:
16,12