A structured jet explains the extreme GRB 221009A

• DOI: 10.1126/sciadv.adi1405
• Publication Date: 2023-06-07T17:58:30Z
• Authors: Brendan O’Connor; Eleonora Troja; Geoffrey Ryan; Paz Beniamini; Hendrik van Eerten; Jonathan Granot; Simone Dichiara; Roberto Ricci; Vladimir Lipunov; James H. Gillanders; Ramandeep Gill; Michael Moss; Shreya Anand; Igor Andreoni; Rosa L. Becerra; David A. H. Buckley; Nathaniel R. Butler; Stephen B. Cenko; Aristarkh Chasovn...; Joseph Durbak; Carlos Francile; Erica Hammerstein; Alexander J. van ...; Mansi M. Kasliwal; Chryssa Kouveliotou; Alexander S. Kutyrev; William H. Lee; Gokul P. Srinivas...; Vladislav Topolev; Alan M. Watson; Yuhan Yang; Kirill Zhirkov
• Keywords: High Energy Astrophysical Phenomena (astro-ph.HE); 570; Multidisciplinary; Earth, Environmental, Ecological, and Space Sciences; 13. Climate action; 0103 physical sciences; FOS: Physical sciences; Astrophysics - High Energy Astrophysical Phenomena; 7. Clean energy; 530; 01 natural sciences

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. Because of its enormous energy ( E iso ≈ 10 55 erg) and proximity ( z ≈ 0.15), GRB 221009A is an exceptionally rare event that pushes the limits of our theories. We present multiwavelength observations covering the first 3 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.