Long duration gamma-ray bursts (GRBs) are powerful cosmic explosions, signaling the death of massive stars. Among them, GRB 221009A is by far the brightest burst ever observed. Due to its enormous energy (Eiso≈1055 erg) and proximity (z≈0.15), GRB 221009A is an exceptionally rare event that pushes the limits of our theories. We present multi-wavelength observations covering the first three months of its afterglow evolution. The X-ray brightness decays as a power-law with slope ≈t−1.66, which is not consistent with standard predictions for jetted emission. We attribute this behavior to a shallow energy profile of the relativistic jet. A similar trend is observed in other energetic GRBs, suggesting that the most extreme explosions may be powered by structured jets launched by a common central engine.
@article{arxiv.2302.07906,
title = {A structured jet explains the extreme GRB 221009A},
author = {B. O'Connor and E. Troja and G. Ryan and P. Beniamini and H. van Eerten and J. Granot and S. Dichiara and R. Ricci and V. Lipunov and J. H. Gillanders and R. Gill and M. Moss and S. Anand and I. Andreoni and R. L. Becerra and D. A. H. Buckley and N. R. Butler and S. B. Cenko and A. Chasovnikov and J. Durbak and C. Francile and E. Hammerstein and A. J. van der Horst and M. Kasliwal and C. Kouveliotou and A. S. Kutyrev and W. H. Lee and G. Srinivasaragavan and V. Topolev and A. M. Watson and Y. H. Yang and K. Zhirkov},
journal= {arXiv preprint arXiv:2302.07906},
year = {2023}
}