Fast radio bursts – those mysterious short yet powerful signals from other galaxies – are pretty rare. While some people claim they’re signals from alien civilizations, others doubt that theory because only two of the dozens discovered so far were repeated from the same location. That theory may have just received some much-needed credibility with the discovery of eight different repeating signals, with one set coming from a nearby galaxy. Can we yell “It’s aliens!” now?
“There is definitely a difference between the sources, with some being more prolific than others. We already knew from FRB 121102 that the bursts can be very clustered: sometimes the source doesn’t burst for hours and hours and then suddenly you get multiple bursts in a short amount of time. We have observed the same thing for FRB 180916.J0158+65, for which we report ten bursts in this paper.”
Physicist Ziggy Pleunis (a top candidate for “Best Astronomer’s Name”) of McGill University is a co-author of the report accepted by the Astrophysical Journal Letters announcing the discovery of eight repeating Fast Radio Burst (FRB) signals using the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. CHIME has been optimized for finding FRBs by searching a wide section of the sky for a lower range of frequencies than most radio telescopes. In an interview with ScienceAlert, Pleunis explained that some of these FRBs repeated only once while one flashed 10 times. Because the intervals between repeating FRBs varied so much in length, some astronomers suspect that all FRBs repeat eventually.
Another interesting observation from these new FRBs is that their wave frequencies get successively lower over time – what the paper calls a “downward frequency drift.” While this could be a sign that whatever is generating the signal is fading away, researchers aren’t ready to call them distress calls from a dying civilization. The polarization of one of the signals showed it came from an extreme magnetic environment – most likely a black hole or a neutron star. Finally, the FRB signals varied in their dispersion. As expected, a highly dispersed signal indicates it has traveled a long distance. One of these eight FRBs had the lowest dispersion rate ever detected, meaning it could be located very close to our galaxy – astronomically speaking, of course.
Speaking of speaking astronomically …
“I think (and I hope!) the paper will prompt other astronomers to point their telescopes to these newly discovered sources. Then, there is a lot of information here for model builders to work with. I think it will help them figure out what produces repeating FRBs. Also, I think our findings will influence the search strategy of other teams that try to discover repeating FRBs.”
Pleunis and the large team of astronomers who co-authored the report are obviously excited about their discovery. Coupled with the recent announcement of development of an AI FRB-detection system, we could be hearing about a lot more repeaters very soon … and hopefully on their origin.
It’s aliens! (We hope!)