Pointing the Very Large Array at a famous galaxy for the first time in two decades, a team of astronomers got a big surprise, finding that a bright new object had appeared near the galaxy’s core. The object, the scientists concluded, is either a very rare type of supernova explosion or, more likely, an outburst from a second supermassive black hole closely orbiting the galaxy’s primary, central supermassive black hole.
Newly obtained radio images of the dramatic bipolar jets of charged particles being ejected from the nucleus of galaxy Cygnus A were able to resolve hotspots in the jets at the places where they impact the surrounding medium. A bright radio galaxy such as this can beam as much as one trillion solar luminosities of radiation into space at those wavelengths.
A computer simulation of the powerful jets generated by supermassive black holes at the centres of the largest galaxies explains why some burst forth as bright beacons visible across the universe, while others fall apart and never pierce the halo of the galaxy. A jet’s hot ionised gas is propelled by the twisting magnetic fields of the central rotating black hole.