I thought it was called a supernova? Did those astronomers change the terminology again? Not the first time I guess Pluto is no longer a planet...
Nova, supernova and hypernova are energetic scales for an "explosive" events in a dying star. The different amount of energies involved relate to different processes that produce these events. Nova is a nuclear explosion due to accretion of material onto a compact object like a neutron star. Supernova is the way some stars end their lives and there are several kinds that depend on the exact scenario. Sometimes it destroys the star completely, sometimes it leaves a neutron star. Hypernova is an even more energetic supernova. It is not exactly clear what happens there, but the common idea is that this is how particularily massive stars end their short lives by collapsing straight into a black hole. It is usually under the broad definition of a supernova.
So, in your opinion they know for sure and understand everything there is to know about the creation and behavior of a black hole?
The pictures imply that because that is what they show. I'd like to see the engineering version then instead of teh cartoon version.
The cartoon intent is only to give a rough illustration and combine different pieces of information into one picture we can keep in our heads. The details in it are far from consensus among astronomers, but they agree on the broad picture of it. Astronomy (and science in general) has developed tools to investigate things that cannot be imaged by a camera. In the case of active galactic nuclear (AGN) the elements in the picture represent a large amount of investigations using spectroscopy, timing analysis and statistical surveys.
Example:
Astronomers see broadened spectral lines that indicate velocity dispersion of 1000s km/sec. These must come from "things" close to a very compact gravitational source (nothing else can create such a dispersion) - depicted as clouds in what is called the "broad line region". From analysis of the variation in brightness in time astronomers know the distance between the central bright light source and reflecting clouds around it - echoes of these variations are seen in the reflected light. From the statistics of how many of these objects appear highly obscured and in how many the light reaches us without much in the way we know that there is thick material around the central source that cover a certain fraction of the sphere around it (depicted as a torus in the images). and so on.