Cygnus X‑1 Jet Measurement
- Astronomers measured the instant power of jets from the black hole binary Cygnus X‑1. (x.com) - The report focused on direct measurement techniques that capture jet power changes in real time. (x.com) - The result provides new observational constraints for how black holes launch and vary their high‑speed jets. (x.com)
Black holes can fire narrow streams of matter called jets, but astronomers have usually had to estimate their strength after the fact. A new study reports a real-time power measurement for the jet in Cygnus X-1. (nature.com) The team used 18 years of high-resolution radio images to watch the jet in Cygnus X-1 get pushed sideways by the wind from its companion star. By modeling that bend, they calculated the jet’s instantaneous kinetic power at about 10^37.3 ergs per second. (nature.com) That is roughly equivalent to the light output of 10,000 suns, and the paper says it is comparable to the system’s total X-ray power from infalling gas. The observations were published April 16, 2026, in *Nature Astronomy* by researchers from Curtin University, the University of Oxford, and collaborators. (physics.ox.ac.uk) (nature.com) Cygnus X-1 is a black hole feeding on material from a blue supergiant star, HDE 226868, in a binary orbit that takes about 5.6 days. Because the star blows a powerful wind, the jet does not stay straight; it “dances” as the pair circle each other. (britannica.com) (ox.ac.uk) Astronomers have long measured jet energy indirectly by studying giant bubbles and rings inflated over years or centuries. The new paper says that method averages over long timescales and cannot track how jet power changes alongside the black hole’s accretion flow in the moment. (nature.com 1) (nature.com 2) That matters because computer models of black hole growth and galaxy evolution often assume how much infalling energy gets diverted into jets. The Cygnus X-1 result gives those models a direct observational anchor from a system close enough to map in detail. (nature.com) Cygnus X-1 has held a special place in astronomy since the early 1970s, when it became the first major black hole candidate to win broad acceptance. It sits about 7,000 light-years away in Cygnus and remains one of the best-studied black hole binaries in the Milky Way. (britannica.com) (nature.com) The researchers also measured the jet speed at about half the speed of light, using the same long-baseline radio data. For a system discovered more than 50 years ago, Cygnus X-1 is still being used to pin down one of black-hole physics’ basic numbers: how much power a jet carries right now. (apnews.com) (nature.com)
