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The Transient Radio Sky

 CSIRO’s 64-metre Parkes radio telescope showing an extragalactic radio burst

Artist’s composite of the CSIRO’s 64-metre Parkes radio telescope showing an extragalactic radio burst appearing briefly, far from the Milky Way’s disk. Credit: Swinburne Astronomy Productions. Background image: astrometry.fas.harvard.edu/skymaps/halpha

By Tara Murphy

With the ability to scan the entire sky each night, the Square Kilometre Array will enable astronomers to catch transient events like gamma-ray bursts and fast radio bursts, as well as phenomena that are so short-lived they have never been detected.

The full text of this article can be purchased from Informit.

The changing sky has always fascinated humans: our ancient ancestors recorded the paths of the planets across the sky in great detail; Aboriginal astronomers used the movements of the stars to plan their travel to new food sources; and throughout history the appearance of “guest stars” – now known to be supernovae – was imbued with deep spiritual significance.

With modern telescopes we have been able to detect the remnants of supernova explosions such as SN 1604, which was observed not only by Kepler but also by Chinese and Korean astronomers. We are still able to detect the radiation from the exploded material as it crashes into the surrounding gas and dust.

The history of astronomy gives us fascinating examples of astronomical objects that vary on human timescales.

What Causes Variability?

Variability gives modern astrophysicists valuable insights into some of the most extreme processes in the universe. Transient objects that appear and disappear, and variable objects that show extreme changes in their brightness can be used as laboratories to investigate the physical processes that cause such variable behaviour.

Radio variability can be classified into a number of categories that represent the physics responsible for that variability:

  • Explosions are usually the cause of the most extreme variable events we observe....

The full text of this article can be purchased from Informit.