14 DAY TRIAL // Astronomers peering over data collected by the Very Long Baseline Interferometry (VLBI) telescope have managed to gain new insight into the structure and dynamics of polar jets coming out of galaxies.
These formation can be seen across the Universe, around objects that have accretion disks. This class of bodies include stars that have just collapsed from their molecular clouds, as well as old neutron stars and black holes.
The accretion disks are agglomerations of matter, that is either leftover from stellar formation, or is being attracted by the immense gravitational pull of collapsed supernova cores.
But perhaps the most impressive jets are produced from stellar and supermassive black holes, as well as from the cores of active galaxies, such as for example quasars.
When quasar radiation jets are oriented towards our planet, therefore allowing us to view them head-on, they are called blazars, Universe Today reports.
The exact mechanisms that underlie the production of such jets are not entirely understood, say astrophysicists. A number of theories to explain the phenomenon do exist however.
The most widely-accepted idea of all is that magnetic lines of force are twisted within an accretion disk, which makes the resulting plasma move away from the core of the disk to the exterior.
As this happens, the matter is being focused into the narrow, but extremely intense jets we see. But investigators admit that the nature of the energy transfer process taking place is still unclear.
Around supermassive black holes, the material needs to be accelerated to nearly the speed of light before it can escape the immense pull of the hole. These jets are often referred to as relativistic jets.
One thing that sets blazars apart from other jet emission sources is that their jets can be seen across the electromagnetic spectrum, emitting a wide variety of radiation.
In the new investigation, VLBI data seem to indicate that blazar jets form within a distance of 10 to 100 times the radius of the supermassive black hole.
An interesting new aspect is that the base of the jets contains formations called shock fronts, which experts believe are in fact points in which magnetically driven flow transforms into kinetic mass flow.
The new investigation does not mean that the physics underlying jet emissions are now understood. Rather, it represents a step forward in shedding more light on this interesting phenomenon.