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In News
- An international team of astronomers have discovered the most distant ‘radio-loud’ quasar with the help of the European Southern Observatory’s Very Large Telescope (ESO’s VLT).
About the Discovery
- It is named P172+18, the quasar emitted wavelengths which had a redshift of 6.8.
- Gravitational redshift occurs as particles of light (photons) climb out of a gravitational well like a black hole and the light’s wavelength gets drawn out. This shifts the wavelength to the red part of the light spectrum – hence “redshift”.
- It took 13 billion years for the quasar’s light to reach earth.
- The higher the redshift of the radio wavelength, the farther away is the source.
- The glowing disc around a blackhole is 300 million times more massive than our Sun.
- It is also one of the fastest accreting quasars, which means it is accumulating objects from the galaxy at an enormous speed.
- Only three other ‘radio-loud’ sources with redshift greater than six have been discovered so far and the most distant one had a redshift of 6.18.
- The scientists think that the powerful radio jets shooting out of the quasar fuelled the appetite of the black hole.
- The jets are thought to be capable of disturbing the gas around the black hole, increasing the rate at which gas falls in.
- Inference: The blackhole at its centre is consuming from its galaxy at a stunning rate.
Significance
- A detailed study of these ‘radio-loud’ super bright objects can help the astronomers to understand how the supermassive black holes in their core grew to be as big so rapidly since the Big Bang.
- The team believes that more such quasars that tell stories about the ancient universe will be found, perhaps even farther away from earth.
What are Quasars?
- Quasi Stellar radio sources, abbreviated QUASARS, are the most dynamic and far-off objects in a collective known as active galactic nuclei (AGN).
- Its spectrum consisted of wide emission lines, unlike stars, thus the name “quasi-stellar.”
- These radiant sources were formed approximately twelve billion years ago.
- Quasar formations take place by the collision of galaxies, i.e., the central black holes merge to form a supermassive black hole.
- Quasars are very luminous objects in faraway galaxies that emit jets at radio frequencies. They are only found in galaxies that have supermassive black holes which power these bright discs.
- However, 90 percent of them do not emit strong radio waves, making this newly-discovered one special.
- Most active galaxies have a supermassive black hole at the centre which sucks in surrounding objects.
- Although quasars were originally discovered due to their radio emissions, only about 10% of quasars have substantial radio emissions.
- These quasars are now called radio-loud quasars.
- Quasars without strong radio emissions are called radio-quiet quasars
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Blackhole
About the ESO’s VLT:
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