Science & Technology
Radio Burst in Milky Way
- 07 Nov 2020
- 6 min read
Why in News
Recently, the National Aeronautics and Space Administration (NASA) has spotted fast Radio Burst for the first time in the Milky Way.
Key Points
- Fast Radio Burst:
- FRB are bright bursts of radio waves (radio waves can be produced by astronomical objects with changing magnetic fields) whose durations lie in the millisecond-scale, because of which it is difficult to detect them and determine their position in the sky.
- It was first discovered in 2007.
- Discovery of FRB in Milky Way:
- NASA observed a mix of X-ray and radio signals never observed before in the Milky Way.
- The X-ray portion of the simultaneous bursts was detected by several satellites, including NASA’s Wind mission.
- NASA’s Wind is a spin stabilized spacecraft launched on 1st November, 1994. After several orbits through the magnetosphere, Wind was placed in a halo orbit around the L1 Lagrange point in early 2004 to observe the unperturbed solar wind that is about to impact the magnetosphere of Earth.
- The radio component was discovered by the Canadian Hydrogen Intensity Mapping Experiment (CHIME), a radio telescope located at Dominion Radio Astrophysical Observatory in British Columbia, which is led by McGill University in Montreal, the University of British Columbia, and the University of Toronto.
- CHIME is a novel radio telescope that has no moving parts. Originally conceived to map the most abundant element in the universe - hydrogen - over a good fraction of the observable universe, this unusual telescope is optimized to have a high "mapping speed".
- Source of FRB in Milky Way:
- The source of the FRB detected recently in the Milky Way is a very powerful magnetic neutron star referred to as a magnetar, called SGR 1935+2154 or SGR 1935, which is located in the constellation Vulpecula and is estimated to be between 14,000-41,000 light-years away.
- The FRB was part of one of the magnetar’s most prolific flare-ups, with the X-ray bursts lasting less than a second.
- The radio burst, on the other hand, lasted for a thousandth of a second and was thousands of times brighter than any other radio emissions from magnetars seen in the Milky Way previously.
- It is possible that the FRB-associated burst was exceptional because it likely occurred at or close to the magnetar’s magnetic pole.
- This flare-up, which lasted for hours, was picked up by NASA’s Fermi Gamma-ray Space telescope and NASA’s Neutron star Interior Composition Explorer (NICER).
- The Fermi Gamma-ray Space Telescope, formerly called the Gamma-ray Large Area Space Telescope (GLAST), is a space observatory being used to perform gamma-ray astronomy observations from low Earth orbit.
- NASA’s Neutron star Interior Composition Explorer is an International Space Station (ISS) payload devoted to the study of neutron stars through soft X-ray timing.
Magnetar
- As per NASA, a magnetar is a neutron star, “the crushed, city-size remains of a star many times more massive than the Sun.”
- The magnetic field of such a star is very powerful, which can be over 10 trillion times stronger than a refrigerator magnet and up to a thousand times stronger than a typical neutron star’s.
- Neutron stars are formed when the core of a massive star undergoes gravitational collapse when it reaches the end of its life. This results in the matter being so tightly packed that even a sugar-cube sized amount of material taken from such a star weighs more than 1 billion tons, which is about the same as the weight of Mount Everest, according to NASA.
- Magnetars are a subclass of these neutrons and occasionally release flares with more energy in a fraction of a second than the Sun is capable of emitting in tens of thousands of years.
- In the case of SGR 1935, for instance, the X-ray portion of the simultaneous bursts it released recently carried as much energy as the Sun produces in a month, assuming that the magnetar lies towards the nearer end of its distance range.
