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Longest-Ever Gamma-Ray Burst Lasts Seven Hours, Afterglow Traced to Dust-Rich Distant Galaxy

Coordinated space-to-ground observations identified a dust-rich host galaxy, leaving the origin uncertain.

Overview

  • Peer-reviewed results in The Astrophysical Journal Letters confirm GRB 250702B as the longest gamma-ray burst observed.
  • Follow-up across infrared, optical, X-ray and gamma-ray bands using VLT, Hubble, Gemini, Magellan and space missions localized the afterglow in a massive, dusty galaxy.
  • Analysis indicates a narrow ultra-relativistic jet aimed toward Earth moving at least 99% of the speed of light.
  • Heavy dust obscuration prevented detection in visible light, making infrared and high-energy measurements crucial to the characterization.
  • Multiple progenitor scenarios remain under study, with current data not uniquely supporting any single explanation.