There are myriad mysteries in the vastness of the universe, but astronomers around the world are particularly enamored with Fast Radio Bursts (FRB) right now. Since discovering the first FRB in the early 2000s, scientists have been trying to identify the source of these intensely powerful electromagnetic signals. A new analysis from NASA has traced the origin of several FRBs back to their home galaxies, which could help scientists narrow down a cause.
The first recorded FRB strobed past Earth in 2001, but scientists didn’t notice it in the data until a later review in 2007. These pulses can release as much energy as the Sun does in an entire year, but they last mere milliseconds. That makes them extremely difficult to study, and until recently we didn’t even know of any repeating FRBs. Bursts that happen on a cycle like FRB 121102 have helped astronomers narrow their theories about what fuels these powerful radio bursts.
Using the Hubble Space Telescope, astronomers were able to trace five FRBs back to their source galaxies, all of which are billions of light-years away. We can’t see into those galaxies to track down the object that emitted the bursts, but just having a general location could help scientists narrow things down. According to the study, which was published in The Astrophysical Journal, all five FRBs came from the spiral arms of distant galaxies.
The observations were made using Hubble’s Wide Field Camera 3 in the ultraviolet and near-infrared spectrum. The ultraviolet spectrum is ideal for tracing the glow of young stars in the spiral arms, and infrared readings helped calculate masses for the galaxies. The source galaxies identified in the study are similar to our own galaxy, and the location in the spiral arms tells us that FRBs probably don’t have anything to do with the youngest, brightest stars when they go supernova. Neutron star mergers are another proposed cause of FRBs, but these collapsed husks of dead stars take billions of years to merge, and these events take place far outside spiral arm regions.
There is one hypothesis that’s supported by the new Hubble research: magnetars. These neutron stars have intensely powerful magnetic fields about a trillion times stronger than Earth’s. The team believes FRBs may happen when young magnetars experience energetic surface events that result in electromagnetic flares. The team characterizes the Hubble results as “exciting,” but we can’t call this one solved quite yet.
Top image credit: NASA / Swift / Aurore Simonnet, Sonoma State University