| Issue |
A&A
Volume 677, September 2023
|
|
|---|---|---|
| Article Number | L3 | |
| Number of page(s) | 6 | |
| Section | Letters to the Editor | |
| DOI | https://doi.org/10.1051/0004-6361/202346373 | |
| Published online | 29 August 2023 | |
Letter to the Editor
Soft gamma-ray spectral and time evolution of the GRB 221009A: Prompt and afterglow emission with INTEGRAL/IBIS-PICsIT
INAF – Istituto di Astrofisica e Planetologia Spaziali, Via Fosso del Cavaliere 100, 00133 Roma, Italy
e-mail: james.rodi@inaf.it; pietro.ubertini@inaf.it
Received:
10
March
2023
Accepted:
28
March
2023
Aims. The gamma-ray burst (GRB) 221009A, with its extreme brightness, has provided the opportunity to explore GRB prompt and afterglow emission behavior on short timescales with high statistics. In conjunction with detection up to very-high-energy gamma rays, studies of this event shed light on the emission processes at work in the initial phases of GRBs’ emission.
Methods. Using INTEGRAL/IBIS’s soft gamma-ray detector, PICsIT (200–2600 keV), we studied the temporal and spectral evolution during the prompt phase and the early afterglow period.
Results. We found a “flux-tracking” behavior with the source spectrum “softer” when brighter. However, the relationship between the spectral index and the flux changes during the burst. The PICsIT light curve shows that afterglow emission begins to dominate at ∼T0 + 630 s and decays with a slope of 1.6 ± 0.2, consistent with the slopes reported at soft X-rays.
Key words: gamma-ray burst: general
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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