Researchers from Breakthrough Listen, a project focused on the search for signs of intelligent life, recently detected a group of 15 Fast Radio Bursts (FRBs) emanating from a dwarf galaxy 3 billion light years from Earth, reports Leah Crane at New Scientist.
The bursts are very strong pulses of radio waves that appear in the sky for just a few milliseconds before disappearing. The pulses were only discovered in 2007, and before the latest batch of pulses was discovered, researchers had only identified a few dozen bursts from regions across the sky. Researchers have one spotted one FRB source, named FRB 121102, that ever repeats.
According to a press release, FRB 121102 is the source of the newly detected radio bursts. Last Saturday, the Breakthrough Listen project turned its Green Bank Telescope in West Virginia towards in the direction of FRB 121102, which a recent study found emanates from a dim, dwarf galaxy in the constellation Auriga. Over the course of five hours, the instrument collected 400 terabytes of data while monitoring the 4 to 8 gighertz frequency. Researchers then combed through the data searching for signatures of the radio bursts. They found 15 of the pulses, including one at 7 gigahertz, which is a higher frequency than previously recorded. They alerted the astronomy world to the find on Monday night by sending out an Astronomer’s Telegram, a venue for astronomers to post real time astronomical events.
The new FRB frequency may be crucial in helping researchers narrow down the sources of the mysterious bursts and may make the signals easier to detect. “Previously we thought there wasn’t much emission at high or low frequencies, but now it looks like there is,” Harvard astrophysicist Avi Loeb tells Crane. “It’s twice as high as the typical frequency that was previously claimed for this repeater.”
Finding out what the bursts are has proven difficult. In February 2015, immediately after detecting a burst named FRB 150215 astronomers trained 11 telescopes and instruments on the area, but did not detect gamma rays, neutrinos or anything left in the wake of the burst.
There are several hypotheses for what the bursts may actually be. As Hannah Osborne at Newsweek reports, the signals could be coming from a neutron star collapsing into a black hole or going supernova. FRBs could also come from a spinning neutron star with a strong magnetic field. Last March, researchers released a paper that suggested it’s possible (but unlikely) that the bursts are coming from alien spacecraft being powered on intergalactic journeys by planet-sized transmitters.
In the past, some astronomers have speculated whether FRBs are even real. As Yvette Cendes wrote for Discover in 2015:
"One particular concern was that the FRB might have originated from nearby thunderstorms, a particularly mundane explanation. Further, radio astronomy is a field with several cases of unexplained anomalous signals. For example, 1977’s “Wow!” signal was a one-time radio burst lasting several minutes that bore the profile of a potential signal from extraterrestrials (hence its designation, coming from an excited researcher’s notes). But no such signal was ever observed again. Without further observations, it is impossible for astronomers to classify it as anything more than a meaningless anomalous signal."
Seth Shostak, a senior astronomer at the California-based SETI Institute tells Alan Boyle at GeekWire that the repeating nature of FRB 121102 has made it easier to study the bursts, but may actually complicate the situation, since that particular FRB may differ from other sources. “The new data are likely to be helpful in figuring out what’s going on here, but of course it could be that this particular object is a member of an ‘FRB subspecies’ – and not typical of most of these weird cosmic screamers,” he says. “Kind of like hearing things growling in the night, eventually seeing one dog, and deducing that anything that growls is two feet high and has a wet nose.”
Vishal Gajjar, the postdoctoral researcher who discovered the bundle of bursts says in the press release that the quality of the data obtained will give researchers an even more precise look at the radio bursts, which could help them figure out, or simply narrow down, their possible origins.