What is a Radio Galaxy?

About Radio Galaxy

• 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. 
• The first radio galaxy to be discovered, and still the brightest, is called Cygnus A.
• 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 Galaxies?

Galaxies are groups of stars and other space objects held together by gravity.Galaxies take on many different shapes and forms throughout the cosmos.There are more than 100 billion galaxies in the universe.

Source: FIRST discovery of dozens of new giant radio galaxies