An artist’s impression of the dust-choked doughnut-shaped torus of rotating debris surrounding the 2.5 billion-solar-mass black hole at the core of Cygnus A, one of the most energetic radio galaxies in the known universe. The direct observation of the torus, a first, appears to confirm a long-theorised model explaining the varied appearances of galaxies featuring active galactic nuclei. Image: Bill Saxton, NRAO/AUI/NSF
For years, astronomers have theorised that energetic galaxies powered by supermassive black holes, whether quasars, blazars, Seyfert galaxies or other varieties are driven by a similar mechanism now collectively known as active galactic nuclei, or AGNs.
The “unified model” describing these enormously powerful galaxies called for a central supermassive black hole, a rotating disk of in-falling gas and dust surrounding the central black hole and jets racing outward from the poles of the disk.
To explain why some of these enigmatic objects look different when observed from different angles, theorists assumed a thick, doughnut-shaped torus of dust surrounding the inner regions that would provide different views depending on the angle between the plane of the galaxy and the observer.
Now, using the Karl G. Jansky Very Large Array (VLA) radio telescope, astronomers have made the first direct observation ...