At the Source of an Extragalactic Jet
Artist's concept of the formation region of M87's jet. An accretion disk (red-yellow) surrounds the black hole, and its magnetic field lines twist tightly to channel the outpouring subatomic particles into a narrow jet. The jet opens widely near the black hole, then is shaped into a narrower beam within a light-year of the black hole.
NASA and Ann Feild (Space Telescope Science Institute)