Fast Radio Bursts (FRBs) are a big fat mystery. The pulses — first discovered about a decade ago — come from billions of light years away and last for just milliseconds. Only 16 pulses have been recorded since the first was heard in 2007, but scientists believe they may occur thousands of times a day. But where do they come from?
In a study published Wednesday in Nature, scientists report our first real clue: The most detailed origin story ever obtained for an FRB. Their findings suggest that these energetic, seemingly random bursts most likely come from a region dense with either the birth or death of stars.
"Hidden within an incredibly massive dataset, we found a very peculiar signal, one that matched all the known characterizes of a Fast Radio Burst, but with a tantalizing extra polarization element that we simply have never seen before," study author Jeffrey Peterson, a faculty member in Carnegie Mellon's McWilliams Center for Cosmology, said in a statement.
By studying the polarization of the burst (its orientation, which happened to be corkscrewed) and other data gleaned from the signal, the researchers were able to determine that the pulse passed through a strong magnetic field — too strong to be from our own galaxy — and then through two different regions of ionized gas. While the second cloud of gas was likely in the Milky Way, the first was much closer to the pulse's origin — probably within its own galaxy. That first wave of ionized gas exposure suggests that the pulse came either from a region surrounded by a nebula or from close to the center of its own galaxy.
"We now know that the energy from this particular burst passed through a dense magnetized field shortly after it formed," Kiyoshi Masui, an astronomer with the University of British Columbia in Canada and lead author of the study, said in a statement. "This significantly narrows down the source's environment and type of event that triggered the burst — and means the source of the pulse likely resides within a star-forming nebula or the remnant of a supernova."
Masui and his colleagues believe that the pulse's origin is no more than 6 billion light years away.
"Taken together, these remarkable data reveal more about an FRB than we have ever seen before and give us important constraints on these mysterious events," Masui said. "We also have an exciting new tool to search through otherwise overwhelming archival data to uncover more examples and get closer to truly understanding their nature."
FRBs still raise plenty of questions, and there's no telling how long astronomers will continue to puzzle over the strange pulses from space. But a vague origin story is better than none at all, and the twists and turns of this corkscrew pulse undoubtedly bring us closer to a satisfying answer.