Correlation between the mass of the galaxies (X-axis) and the difference of their radio emissions at different radio frequencies (Y-axis). Each symbol represents an individual galaxy. The image of an example galaxy is from NASA/ESA Hubble Space Telescope T means the time for light to travel from these galaxies to us.
Credit: Fangxia An (IDIA/UWC)
From Phys.org and The Conversation,
Using the Meerkat Telescope on over 2,000 radio galaxies...