Free Astronomy Magazine March-April 2026

41 ASTRO PUBLISHING MARCH-APRIL 2026 T his artist’s illustration, which shows a high-speed jet of material being launched from a source that is embedded in a very dusty galaxy, depicts GRB 250702B — the longest gamma-ray burst that astronomers have ever observed. This powerful, extragalactic explosion was first detected on 2 July 2025. It exhib- ited repeated bursts that lasted over seven hours. Astronomers conducted rapid follow-up observations with multiple telescopes around the world and found that GRB 250702B resides in a large, extremely dusty galaxy. Their data support a range of progenitor scenarios, including interactions between a star and a black hole, or possibly a neutron star. [NOIRLab/NSF/AURA/M. Garlick] A stronomers have observed the longest-ever gamma-ray burst — a powerful, extragalactic explosion that lasted over seven hours. Rapid follow-up obser- vations with the U.S. Department of Energy-fabricated Dark Energy Camera and the International Gemini Observatory, funded in part by the U.S. National Sci- ence Foundation and operated by NSF NOIRLab, provided crucial information about the possible origin of this extraordinary event and the galaxy that hosts it. [International Gemini Observatory/NOIRLab/NSF/AURA/M. Garlick. Image pro- cessing: M. Zamani & D. de Martin (NSF NOIRLab). Motion graphics: M. Garrison] rays and pinpointed its on-sky loca- tion in X-rays, astronomers around the world launched campaigns to observe the event in additional wavelengths of light. One of the first revelations about this event https://noirlab.edu/public/videos/noirlab2531c/ came when infrared observations ac- quired by ESO’s Very Large Telescope (VLT) established that the source of GRB 250702B is located in a galaxy outside of ours, which until then had remained a question. Following this, a team of astronomers led by Jonathan Carney, graduate student at the University of North Carolina at Chapel Hill, set out to capture the event’s evolving afterglow, or the fading light emissions that follow the initial, extremely bright flash of gamma-rays. The properties of these emissions can provide clues about the type of event that caused the GRB. To better understand the na- ture of this record-breaking event, the team used three of the world’s most powerful ground-based tele- scopes: the NSF Víctor M. Blanco 4- meter Telescope and the twin 8.1- meter International Gemini Obser- vatory telescopes. This trio observed GRB 250702B starting roughly 15 hours after the first detection until about 18 days later. The team pre- sented their findings in a paper pub- lished in The Astrophysical Journal Letters . The Blanco telescope is lo- cated in Chile at NSF Cerro Tololo Inter-American Observatory (CTIO), a Program of NSF NOIRLab. The In- ternational Gemini Observatory con-