How do jets form near some quasars?
Shown are apparently normal, solitary galaxies (left), colliding galaxies (centre), and merging galaxies (right).
In some quasars, jets are formed as highly collimated beams of plasma that are propelled outward along the rotation axis of the accretion disk surrounding a supermassive black hole.1
These jets consist of relativistic particles—material traveling at speeds approaching that of light—that transport energy from the active galactic nucleus to more distant regions, such as radio lobes. The appearance of these jets can be influenced by relativistic effects, such as the Doppler shift, which can cause a jet pointed toward an observer to appear significantly brighter than its counterjet.12
The underlying energy for these phenomena is supplied by the central engine of the active galaxy, where gravitational accretion onto the black hole powers the emission. While the exact mechanisms of jet formation are complex, they are understood as fundamental features of the physical structure of quasars, with their observed prominence depending heavily on the orientation of the accretion disk's rotation axis relative to the observer's line of sight.12