Astronomers around the world are captivated by an unusually bright and long-lasting pulse of high-energy radiation that swept over Earth Sunday, Oct. 9. The emission came from a gamma-ray burst (GRB) – the most powerful class of explosions in the universe – that ranks among the most luminous events known.
On Sunday morning Eastern time, a wave of X-rays and gamma rays passed through the solar system, triggering detectors aboard NASA's Fermi Gamma-ray Space Telescope, Neil Gehrels Swift Observatory, and Wind spacecraft, as well as others. Telescopes around the world turned to the site to study the aftermath, and new observations continue.
The signal, originating from the direction of the constellation Sagitta, had traveled an estimated 1.9 billion years. Astronomers think it represents the birth cry of a new black hole, one that formed in the heart of a massive star collapsing under its own weight. In these circumstances, a nascent black hole drives powerful jets of particles traveling near the speed of light. The jets pierce through the star, emitting X-rays and gamma rays as they stream into space.
According to a preliminary analysis, Fermi’s Large Area Telescope detected the burst for more than 10 hours. One reason for the burst's brightness and longevity is that, for a GRB, it lies relatively close to us, but it’s also among the most energetic and luminous bursts ever seen regardless of distance. Another GRB this bright may not appear for decades.