Very High Energy Afterglow Emission of GRB~221009A: Lessons Learned from the Brightest Long Gamma-ray Burst in a Wind Environment [HEAP]

http://arxiv.org/abs/2210.10673


In this paper, we modeled the dynamics and radiation physics of the rarity event GRB 221009A afterglow in detail. Based on the analysis results of the {\tt ASGARD} package we developed, the afterglow data of GRB 221009A strongly favors the origin of a relativistic jet propagating in a stellar-wind-dominated environment. Therefore, GRB 221009A is a typical lesson for the very high energy (VHE) afterglow of long gamma-ray burst in a wind environment. We also show the broadband spectral energy distribution (SED) analysis results of GRB 221009A, and find that the synchrotron self-Compton (SSC) radiation component of GRB 221009A is very bright in the $0.1-10$ TeV band. The integrated SED of $0-2000$ s after {\em Fermi}/GBM trigger shows that the bright SSC component can be easily observed in TeV band, above the detection sensitivity of LHASSO, MAGIC and CTA. We predict that the SSC radiation peak flux of GRB 221009A in the first 2000 second integral SED is $\sim 10^{-7}~\rm erg~cm^{-2}~s^{-1}$, with a peak energy close to 300 GeV. Furthermore, we find that the inclusion of GeV observations could break the degeneracy between model parameters, highlighting the significance of high-energy observations in determining accurate parameters for GRB afterglows.

Read this paper on arXiv…

J. Ren, Y. Wang and L. Zhang
Thu, 20 Oct 22
38/74

Comments: 11 pages, 5 figures, comments are welcome