Weekly Current Affairs

Notice

Two ‘monster’ black holes hiding in cosmic backyard spotted

  • Scientists, using data from National Aeronautics and Space Administration (NASA) telescopes, have spotted two supermassive black holes, located at the centres of galaxies close to our Milky Way, that were hidden behind shrouds of gas and dust until now.
  • Monster black holes sometimes lurk behind gas and dust, hiding from the gaze of most telescopes.
  • However, they give themselves away when material they feed on emits high-energy X-rays that NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) mission can detect.
  • Both of the black holes are the central engines of what astronomers call “active galactic nuclei,” a class of extremely bright objects that includes quasars and blazars.
  • Depending on how these galactic nuclei are oriented and what sort of material surrounds them, they appear very different when examined with telescopes.
  • Active galactic nuclei are so bright because particles in the regions around the black hole get very hot and emit radiation across the full electromagnetic spectrum— from low-energy radio waves to high-energy X-rays.
  • However, most active nuclei are believed to be surrounded by a doughnut-shaped region of thick gas and dust that obscures the central regions from certain lines of sight.
  • That means that instead of seeing bright central regions, our telescopes primarily see the reflected X-rays from doughnut-shaped obscuring material.
  • Findings from NuSTAR confirm nature of IC 3639 as active galactic nucleus.
  • The black hole in its centre was discovered in 2009, even though it is only 38 million light years away.