PoS - Proceedings of Science
Volume 444 - 38th International Cosmic Ray Conference (ICRC2023) - Gamma-ray Astronomy (GA)
Cosmic-ray origin of $\gtrsim 10$ TeV gamma-rays in GRB~221009A
S. Das* and S. Razzaque
Full text: pdf
Pre-published on: July 25, 2023
Published on:
On October 9, 2022, the Swift-BAT and Fermi-GBM telescopes detected the brightest long gamma-ray burst (GRB) observed so far. This provides us an opportunity to understand the high-energy processes in extreme transient phenomena. High-energy photons upto $\gtrsim 10$ TeV, and as high as 18 TeV were detected by the LHAASO detector. Conventional leptonic models such as synchrotron and synchrotron self-Compton are insufficient to explain the emission of such high-energy photons in the afterglow phase. In this work, we use a leptonic model for the flux of $\gamma$-rays observed by the Fermi-LAT detector in the energy range of 0.1-1 GeV. This flux is severely attenuated due to $\gamma\gamma$ pair production interaction with the extragalactic background photons. We invoke an alternate process for the explanation of the high-energy photons originating in ultrahigh-energy cosmic rays. These cosmic rays, accelerated in the GRB blastwave can escape the source and initiate an electromagnetic cascade in the extragalactic medium. The resulting $\gamma$-ray flux along our line of sight can explain the observation of $\gtrsim10$ TeV photons, detected by LHAASO, requiring a fraction of the GRB blastwave energy in ultrahigh-energy cosmic rays. This can be the first indirect signature of ultrahigh-energy cosmic-ray acceleration in GRBs.
DOI: https://doi.org/10.22323/1.444.0668
How to cite

Metadata are provided both in "article" format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in "proceeding" format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.