Black holes are one of those rare objects that are so weird that they get a whole lot of attention. And when I say they are weird, I mean they gift researchers with utterly unexpected things on a regular basis. In another system, GRS 1915+105, researchers found the system changes over a 500-ish day period in a way they liken to a heart. Located in a binary system, this roughly twelve solar mass black hole steals material from its companion, and that material is excited into a corona around the black hole and driven into jets.

This work is published in Nature Astronomy and was led by Mariano Méndez.

For fifteen years, a team monitored this system with the orbiting Rossi X-ray Timing Explorer and the Ryle radio telescope outside London. In this data, they found a roughly 500-day cycle, with the radio and X-ray data reaching their separate peak brightnesses when the other light was faint.

This was the first time both aspects of a system were so thoroughly observed, and this remarkable data set allowed them to determine that the corona and jets are directly related. According to the paper’s abstract, the system’s X-ray corona can transform into radio jets. This is driven by thermal instabilities.

To try and explain this as simply as possible: material builds up in the corona where it emits X-ray light. At a certain point, this built-up material collapses into jets, the X-ray light goes away, and the radio light brightens, feeding the jets. This reminds me of those water features at amusement parks where water builds up in a bucket until it becomes unstable and flips to dump water all over anyone below.

Black holes do weird things. And this is your lesson for today: do not park your spacecraft below a black hole — it just might get a radio jet dumped on it.

More Information

NOVA press release

“Coupling between the accreting corona and the relativistic jet in the microquasar GRS 1915+105,” Mariano Méndez et al., 2022 March 7, Nature Astronomy