At a lot of different levels, the most interesting things in the sky are the things that vary in brightness. We see long and short period variations in every color and at every size scale. Our sky is active and constantly changing – we just can’t make out the majority of these changes with our eyes.
But telescopes can.
In the past decade, researchers using radio telescope data discovered a new kind of behavior. Sources somewhere out there have been shooting out massive amounts of radio light for very brief periods of time. Sometimes the events can occur in repeating clusters of the source being active and not active. Sometimes things have only been caught varying once. It is all a bit mysterious, and for lack of a better name for this mystery, these flashes have been called “fast radio bursts”.
In recent years many of these events have been linked to tiny but dense objects called magnetars. These objects are the remnants of once massive stars that have gone supernova and have left behind a neutron star in the process; a neutron star that, in some cases, ends up with a powerful magnetic field.
Unfortunately for astronomers, the universe often has more than one way to create an observable phenomenon.
1,863 bursts were discovered by China’s massive FAST radio dish in spring 2021. This is the largest sample set to date, and not all of these objects match what we’ve seen in the past. In fact, team member Bing Zhang states: These observations brought us back to the drawing board. It is clear that FRBs are more mysterious than what we have imagined.
The most distant sources they observed are totally mysterious, but they were able to see one relatively nearby system that stopped and started in ways we haven’t seen before. While they still seem consistent with a magnetar being at the heart of the emissions, what they saw doesn’t match the behavior of an isolated star.
This paper is published in Nature and led by the team of Heng Xu, Kejia Lee, and Subo Dong and raises more questions than it answers, but that is kind of awesome. The more questions we have to answer, the more reasons we have to do science.
UNLV press release
“A fast radio burst source at a complex magnetized site in a barred galaxy,” H. Xu et al., 2022 September 21, Nature