Snapshot: M87’s twisted jet

Propelled by the supermassive black hole’s magnetic field, this jet stretches to galactic proportions.
By | Published: December 21, 2021 | Last updated on May 18, 2023
Pasetto et al., Sophia Dagnello, NRAO/AUI/NSF.

The subject of the first ever image of a black hole, M87’s supermassive black hole (SMBH) has drawn scientists’ attention once more thanks to its jet. Emanating from the heart of the galaxy, the jet stretches nearly 3,300 light-years in length and, thanks to research published Dec. 7 in The Astrophysical Journal Letters, is evidently directed by the SMBH’s helix-shaped magnetic field.

SMBH’s are known to produce relativistic jets as they gobble down nearby material. As particles are driven faster and faster around the black hole, some of them are thrown out at speeds close to the speed of light into narrow beams.

“Helical magnetic fields are expected close to the black hole and are thought to play a highly important role in channeling the material into a narrow jet, but we didn’t expect to find such a strong helical field extending so far outward,” said co-author Jose M. Marti, of the University of Valencia, in a press release.

But these magnetic fields are expected to weaken the further they get from their source, M87’s jets suggest something else must be going on to maintain the magnetic field to that distance. The team suggests that instabilities within the material may be causing pockets of high-pressure areas which causes the magnetic field to remain strong out to thousands of light-years.