Fast Radio Bursts
Context:
- Mysterious radio light emissions from the remote reaches of the universe are the next big thing in radio astronomy. Fast radio bursts (FRBs) are brief bursts of radio waves that arrive on Earth from distant galaxies, generating as much energy in a millisecond as the sun does in weeks.
FRBs:
- We know very little about the precise origins of FRBs and why they emerge in such brief, sharp bursts – save that these celestial electromagnetic impulses are most likely emitted by dying stars.
- Some FRBs are ‘one-off’ events, discovered once and never seen again; others are repeaters, flashing Earth occasionally like a ghostly lighthouse in the depths of space.
- An international team of astronomers has now published the findings of their extensive study on a repeated FRB from a faraway galaxy, which provides new insights into the origins of these strange radio flashes.
- They used the Green Bank Telescope in the United States and the Parkes Observatory in Australia to observe a recurring FRB dubbed FRB 20190520B and captured hundreds of bursts from it.
Findings:
- They noticed that the FRB’s Faraday rotation measure, which indicates the strength of its magnetic field, was highly variable and reversed direction twice.
- They believe the magnetic reversal is caused by the FRB source circling a binary star system in which the companion star is most likely a big star or a black hole.
- They discovered that the magnetic field value and electron density varied around this source, indicating an extremely turbulent magnetised plasma environment.
The findings are summarised as follows:
- This finding is consistent with an earlier discovery of a nearly identical binary system in the Milky Way galaxy, complete with magnetic field reversal.
- To reach a final decision, these FRBs must be continuously monitored over time.
- Cosmologists hope that learning more about such changes in the magnetised environment around FRBs would eventually aid in the discovery of their origins.
- Astronomers have a new generation of radio telescopes at their disposal to accomplish this.
Radio astronomy:
- Until the early 1930s, astronomers relied on the limited visible section of the electromagnetic spectrum to conduct observations, oblivious to the vast potential of the radio band at the opposite end of the spectrum.
- Because of their long wavelengths, radio waves can travel through intergalactic space without interruption, making them a suitable tool for detecting radio emissions from distant heat sources.
- Fortunately, scientists who made pioneering discoveries persisted and inspired others to develop radio astronomy, which has allowed us to learn about intergalactic phenomena such as pulsars (fast spinning neutron stars), dark matter, the cosmic microwave background (signals left over from the universe’s birth), and, of course, FRBs.
- Radio astronomers now have telescopes that can pinpoint FRBs with arc-second precision, allowing them to search for the FBR’s home galaxy with other wavelengths.
Conclusion:
- Astronomers aim to answer cosmic mysteries and get a greater understanding of the cosmos by connecting dots like these.
