Theoretical Modeling of the Exceptional GRB 221009A Afterglow
Sep 4, 2024
10 pages
Published in:
- Astrophys.J.Lett. 973 (2024) 2, L44
- Published: Sep 24, 2024
e-Print:
- 2409.02859 [astro-ph.HE]
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Abstract: (IOP)
The extraordinary gamma-ray burst GRB 221009A provides a great opportunity to investigate the enigmatic origin and evolution of gamma-ray bursts (GRBs). However, the complexity of the observations associated with this GRB provides significant challenges to developing a theoretical modeling in a coherent framework. In this paper, we present a theoretical interpretation of the GRB 221009A afterglow within the relativistic fireball scenario, aiming to describe the broadband data set with a consistent model evolution. We find that the adiabatic fireball evolution in the slow-cooling regime provides a viable scenario in good agreement with observations. Crucial to our analysis is the set of simultaneous GeV and TeV gamma-ray data obtained by AGILE and LHAASO during the early afterglow phases. Having successfully modeled as inverse Compton emission the high-energy spectral and lightcurve properties of the afterglow up to 10 s, we extend our model to later times when also optical and X-ray data are available. This approach results in a coherent physical framework that successfully describes all observed properties of the afterglow up to very late times, approximately 10 s. Our model requires time-variable microphysical parameters, with a moderately increasing efficiency ε of a few percent for transferring the shock energy to radiating particles and a decreasing efficiency for magnetic field generation ε in the range 10–10. Fitting the detailed multifrequency spectral data across the afterglow provides a unique test of our model.Note:
- Published in ApJL
References(60)
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