Indian Telescope Spots Distant Radio Galaxy

• 10 Aug 2018

The scientists have discovered the most distant radio galaxy ever known, located at a distance of 12 billion light-years.

• The discovery was done after studying the data derived from a sky survey done by the Giant Metrewave Radio Telescope (GMRT) in Pune seven years ago.
• However, the distance of this galaxy was determined using the Gemini North telescope in Hawaii and the Large Binocular Telescope in Arizona.
• This radio galaxy belongs to a time when the universe was only seven per cent of its current age. This also means that the light from this galaxy is almost 12 billion years old.
• The unraveling of such radio galaxies at large distances is important for understanding of the formation and evolution of galaxies, and formation of primordial black holes.
• The Centaurus A is the closest radio galaxy at only 10 million light years away from the Earth.

Giant Metrewave Radio Telescope

• GMRT is an array of thirty fully steerable parabolic radio telescopes of 45 metre diameter. It is operated by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research.
• GMRT is an indigenous project. Its design is based on the `SMART' concept - for Stretch Mesh Attached to Rope Trusses.
• It functions at the metre wavelength part of the radio spectrum because man-made radio interference is considerably lower in this part of the spectrum in India and there are many outstanding astrophysics problems which are best studied at metre wavelengths.
• The location for GMRT, Pune meets several important criteria such as low man-made radio noise, availability of good communication, vicinity of industrial, educational and other infrastructure and,a geographical latitude sufficiently north of the geomagnetic equator in order to have a reasonably quiet ionosphere and yet be able to observe a good part of the southern sky as well.

Radio Galaxy

• Radio galaxies are very rare objects in the universe. They are extremely large galaxies with a supermassive black hole in their centre that actively accumulates gas and dust from its surroundings.
  • Black Hole is a place in space where gravity pulls so much that even light can not get out. The gravity is so strong because matter has been squeezed into a tiny space. This can happen when a star is dying.
• The accumulation of gas and dust initiates the launch of high-energy jet streams, which are capable of accelerating charged particles around the supermassive black hole to almost the speed of light.
  • These jet streams are very clearly observed at radio wavelengths.
• Radio galaxies and Quasars (believed to be a radio galaxy viewed down the length of the jet) are some of the brightest objects in the universe.
  • The word quasar is short for "quasi-stellar radio source", which means star-like emitters of radio waves. However, most quasars are faint radio emitters.
  • In addition to radio waves and visible light, quasars also emit ultraviolet rays, infrared waves, X-rays, and gamma-rays.
  • Most quasars are larger than our solar system.