We know much more about how the universe works today than we did just a few decades ago, but there will always be new mysteries to solve. In recent years, scientists have puzzled over the riddle of fast radio bursts (FRBs). These short-lived electromagnetic beacons can outshine entire galaxies, and we haven’t been able to figure out what causes them. A trio of new studies report on an FRB within our own galaxy. Because this one was so much closer than past signals, scientists were able to track it to a particular type of neutron star known as a magnetar.
Despite the immense amount of energy emitted during an FRB, scientists didn’t know they existed until 2007. That’s when a team discovered the first FRB hiding in data acquired back in 2001. Since then, astronomers have spotted numerous FRBs throughout the cosmos. However, this phenomenon seemed to be non-repeating until the discovery of FRB 121102. We now believe this radio source operates on a 157-day cycle, which makes it easier to study.
With the data from FRB 121102, magnetars merged as a plausible candidate. Like pulsars, magnetars are a subset of neutron stars. They don’t spin as quickly as a pulsar, but they have an incredibly intense magnetic field. At about a trillion times as strong as Earth’s magnetic field, a magnetar can disrupt the electron orbitals in molecules, essentially halting chemistry in any normal matter that gets too close.
That brings us to SGR 1935 2154, a magnetar about 30,000 light-years away. That’s not close by any means, but it’s still inside the Milky Way. Back in April, this dead star woke up and began firing off high-energy photons, which was normal. However, two instruments were on the hunt for FRBs at the same time, and that’s what they found exactly when SGR 1935 2154 lit up the sky. Both the Canadian Hydrogen Intensity Mapping Experiment (CHIME) and Survey for Transient Astronomical Radio Emission 2 (STARE2) detected an FRB from this object.
We can’t call this one solved quite yet, though. As the researchers point out in the papers, the apparent FRB from SGR 1935 2154 was only about one percent as powerful as the FRBs we’ve seen from outside the galaxy. It’s possible only very young and energetic magnetars can produce bursts visible from a few galaxies away. Perhaps SGR 1935 2154 is displaying the same phenomenon at a lower level of power. If the team can prove that this object produced FRBs, we can refine our models and hopefully mark this one down as solved.