The birth cry of a Black Hole: Brightest gamma-ray burst reveals new cosmic explosion mysteries 

Astronomers intrigued by the brightest gamma-ray burst ever detected, believed to be the birth cry of a black hole, are uncovering new puzzles about cosmic explosions. 

Unprecedented gamma ray burst event

On October 9, 2022, a powerful gamma-ray pulse passed through our solar system, overwhelming the gamma-ray detectors on many orbiting satellites and prompting astronomers to use the most powerful telescopes. world to investigate the event. The newly discovered source, designated GRB 221009A, is the brightest gamma-ray burst (GRB) ever recorded.

In a study published in The Astrophysical Journal Letters, observations of GRB 221009A on the radio gamma-ray spectrum reveal important insights into the origin of these violent cosmic explosions, a decades-long pursuit of astronomers.

The birth cry of a black hole

Gamma-ray emission from GRB 221009A persisted for more than 300 seconds. Long-lived GRBs like these are thought to signal black hole formation when the core of a rapidly rotating massive star collapses under its own weight. The nascent black hole produces jets of plasma close to the speed of light that pass through the collapsing star and emit gamma rays.

Unravel the mysteries of the halo

The real puzzle with GRB 221009A, the brightest on record, is what happens after the initial gamma-ray burst. When the rays collide with surrounding gas, they create an “afternoon” of full-spectrum light that quickly fades, said Tanmoy Laskar, lead author of the study. SMA, run by the Center for Astrophysics | Harvard & Smithsonian, was used by astronomers to capture the halo before it disappeared.

Surprise observation

The resulting data is confusing because the millimeter measurements and radio waves are much brighter than expected based on visible light and X-rays. According to CfA researcher Yvette Cendes, a single mechanism is likely responsible for generating excess millimeters and radio waves. The powerful jet stream generated by the GRB 221009A can be more complex than most GRBs, with visible light and X-rays emanating from part of the jet stream as well as millimeter waves and early radio waves from the portion of the jet stream. other.

Continually uncovering cosmic mysteries

The halo is so powerful that astronomers will study its radio emission for months or even years to determine the mysterious source of the excess emission. Rapid response to GRBs and similar events using millimeter-wave telescopes, such as SMA, is an essential new capability for astronomers as it allows for potential discovery of such events. The most massive explosion in the universe.

“This explosion, so bright, provided a unique opportunity to explore the detailed behavior and evolution of the aura in unprecedented detail – we didn’t want to miss it!” Edo Berger, a professor of astronomy at Harvard University and the CfA. “I’ve been studying these events for over twenty years and this event is as exciting as the first GRB I ever observed.”