Glowing plasma jets shoot away from a black hole in this artist’s rendering.

Glowing plasma jets shoot away from a black hole in this artist’s rendering. ESO/WFI (visible); MPIfR/ESO/APEX/A. Weiss et al. (microwave); NASA/CXC/CfA/R. Kraft et al. (X-ray)

Astronomy and astrophysics

A black hole’s jets light up in less than a second

Plasma jets start to shine just after less-fortunate material swirls towards its doom.

Plasma jets shot from a black hole take about 0.1 seconds to start glowing.

Material spiralling towards a black hole emits X-rays. But some matter manages to escape ingestion and form plasma jets, which stream into space and then start to glow with visible light. A team led by Poshak Gandhi at the University of Southampton, UK, observed this process by training the William Herschel Telescope in La Palma, Spain, and NASA’s NuSTAR orbital telescope on a black hole in the Cygnus constellation.

As the densest chunks of matter approached the black hole, they gave off especially bright X-rays, but there was no immediate spike in visible light. Instead, corresponding flares of visible light lagged an average of 0.1 seconds behind the X-rays. That lag represents the time that it takes for a jet to start glowing.

These measurements will help to refine theories about why the jets shine, the scientists say.