We looked at data from the GaLactic and Extragalactic All Sky MWA (GLEAM) survey, which sees the sky at 20 different radio frequencies, giving astronomers an unparalleled “radio colour” view of the sky.įrom the data, baby radio galaxies appear blue, which means they’re brighter at higher radio frequencies. Old ones are red, babies are blueīoth young and old radio galaxies can be identified by a clever use of modern radio astronomy: looking at their “radio colour”. The second theory to explain smaller lobes is the jets are young and have not yet extended to great distances.
It’s still unclear whether the lobes are only temporarily confined by a small, extremely dense surrounding environment - or if they’re slowly pushing through a larger but less dense environment. However, the details around this phenomenon remain unknown. One is that the jets are held back by dense material around the black hole, often referred to as frustrated lobes. It can be hundreds, thousands or even millions of light years across and therefore can take aeons to show any dramatic changes.Īstronomers have long questioned why some radio galaxies host enormous lobes, while others remain small and confined. This entire structure is what makes up a radio galaxy, so called because it gives off a lot of radio-frequency radiation. Here it is pictured emitting high energy particles in jets expanding out into radio lobes. The radio galaxy Hercules A has an active supermassive black hole at its centre.