What are Radio Galaxies?

1 min read
What are Radio Galaxies? Blog Image


A team of astronomers from the National Centre of Radio Astrophysics (NCRA) Tata Institute of Fundamental Research (TIFR) Pune; Physical Research Laboratory (PRL) Ahmedabad; and the University of Oxford recently discovered several ‘elusive dying radio galaxies’.

About Radio Galaxies:

  • Radio Galaxies, also known as radio-luminous galaxies or radio-loud galaxies, are a particular type of active galaxy that emits more light at radio wavelengths than at visible wavelengths.
  • These happen through the interaction between charged particles and strong magnetic fields related to supermassive black holes at the galaxies’ center.
  • Radio galaxies are driven by non-thermal emissions.
  • They are much bigger than most of the other galaxies in the universe. 
  • There are two broad classes of radio galaxies:
  • Core-halo radio galaxies:
  • They exhibit radio emission from a region concentrated around the nucleus of the galaxy.
  • The region of radio emission is comparable in size to the optically visible galaxy.
  • Lobed radio galaxies:
  • They display great lobes of radio emission extending, in some cases, for millions of light years beyond the optical part of the galaxy.
  • Some radio galaxies have a single lobe, but more often, the lobes are double, arrayed on both sides of the optical galaxy.



Q1) What are supermassive black holes?

Supermassive black holes contain between one hundred thousand and ten billion times more mass than our Sun. As of 2022, there are over 150 confirmed supermassive black holes in our local Universe (with direct mass measurements). They typically exist at the centre of large galaxies, including the centre of our own galaxy, the Milky Way.

Source: Astronomers discover ‘Elusive Dying Radio Galaxies’ using deep radio surveys