Active Galactic Nucleus

Artistic representations of the nucleus of an active galaxy, created in 2016 to illustrate my PhD thesis. Drawn in negative using a 0.5 mm mechanical pencil with a grade 2B lead, and then inverted in Photoshop.

A supermassive black hole is accreting material from a disk that's bigger than the entire Solar System and so hot that shines incredibly bright in the center, which is surrounded by a torus of dust several light years across. The inner edge of the torus is at the distance where dust grains cannot form closer to the center because they sublimate due to the high temperature, and this opening allows hot gas to be pushed away forming a biconical region that shines with the colours of the spectral lines of the elements forming it. Also, powerful jets of matter moving at relativistic speeds are emitted from the center of the system, and will shine in radio waves as the charged particles are accelerated in their magnetic fields.