Brightest Gamma Ray Burst Detected | 01 Apr 2023

Why in News?

In October 2022, astronomers recorded the brightest gamma-ray radiation (named GRB 221009A) of all time, which could overturn a long-standing theory of GRB jets.

• The observation was conducted jointly by Center for Astrophysics, Harvard and Smithsonian’s Submillimeter Array (SMA) in Hawaii, the MeerKAT Array in South Africa, the US National Science Foundation’s Karl G Jansky Very Large Array (VLA) in New Mexico (USA), the Atacama Large Millimeter Array (ALMA) in Chile and NCRA’s Giant Metrewave Radio Telescope, India.

What is a Gamma-Ray Burst?

• About:
  • Gamma-Ray Bursts are the most powerful class of explosions in the universe, and they occur when massive stars die.
  • When a massive star collapses, it creates a black hole, and the energy released during this process produces jets of high-energy particles that travel almost at the speed of light.
    • These jets pierce through the collapsing star, producing X-rays and gamma rays, which can be detected by observatories on Earth and in space.
• Types of GRBs:
  • Long-duration gamma-ray bursts (LGRBs):
    • LGRBs last for more than two seconds and are thought to be caused by the collapse of massive stars, known as supernovae.
    • These explosions release a tremendous amount of energy and create a black hole at their center.
    • LGRBs are the most common type of GRB and can be observed from distant galaxies.
  • Short-duration gamma-ray bursts (SGRBs):
    • SGRBs last for less than two seconds and are thought to be caused by the collision of two compact objects, such as neutron stars or a neutron star and a black hole.
    • SGRBs are much rarer than LGRBs, are more difficult to observe and typically located closer to our galaxy.

What is GRB 221009A?

• About:
  • GRB 221009A was detected in October 2022, by NASA's Fermi Gamma-ray Space Telescope, Neil Gehrels Swift Observatory, and Wind spacecraft.
  • The signal originated from the direction of the constellation Sagitta, and it took approximately 1.9 billion years to reach Earth.
  • The 5-minute-long radiation pulse was the brightest GRB ever and nearly 70 times brighter than any other such eruption ever observed.
• Observation from GRB 221009A:
  • The pulse of radiation was unusually bright and long-lasting, which made it stand out from other gamma-ray bursts.
  • The signal triggered detectors at multiple observatories, indicating its strength and duration.
• Researchers about 221009A:
  • "Long-duration" GRBs occur when the core of a massive star collapses under its own weight, giving birth to a black hole.
  • This formation produces powerful plasma jets that shoot gamma rays at almost the speed of light. When these jets collide with the gas surrounding the dying star, a bright afterglow is produced across the spectrum.
• Significance:
  • Astronomers from the National Centre for Radio Astrophysics in India concluded that the signal was a birth cry of a black hole.
  • GRB 221009A provides astronomers with valuable insights into the formation of black holes and the mechanisms that produce gamma-ray bursts.
  • The detection of GRB 221009A will help astronomers refine their understanding of the conditions required for the formation of black holes and the production of gamma-ray bursts.

Source: DTE