A team of scientists in Canada have found a Fast Radio Burst (FRB) that repeats every 16 days. This is in stark contrast to other FRBs, which are more sporadic. Some of those sporadic FRBs occur in clusters, and repeat irregularly, but FRBs with a regular, repeatable occurrence are rare.
A Fast Radio Burst is a pulse of radio emissions that lasts only milliseconds. The first one was discovered in 2007 by astrophysicist Duncan Lorimer and his student David Narkevic, and is called the Lorimer Burst. Since that time, many more have been discovered, but their origin is still unclear, though we know their source is extra-galactic.
The new burst is called FRB 180916.J0158+65, and it represents an unusual opportunity. Since most FRBs don’t repeat, there’s no way to do follow-up observations. But FRB 180916.J0158+65 repeats about every 16 days. There are about 10 other known FRBs that repeat, but they don’t repeat regularly.
In this case, the researchers were studying data from CHIME. Once they spotted this new FRB, they looked at past data, and found 400 observations of the new FRB. They determined that it repeats 16.35 days. The signals arrived about once every hour for a four day period, and then stop. Then about 12 days later they’d start up again.
Astronomers have been able to pinpoint the origin of the new FRB. It’s coming from an active star-forming region in a nearby massive spiral galaxy. It’s one of only four FRBs to have its source pinpointed like this, and of those four, it’s the only repeater.
Since astrophysicists still don’t know what creates FRBs, pinpointing their sources is a key part of understanding them. While this latest FRB is coming from a star-forming region in a spiral galaxy about 500 million light years away, other FRBs appear to have different sources. One, for instance, came from a low-metallicity irregular dwarf galaxy, indicating that there may be more than one source for FRBs.
Source: “A Rare Fast Radio Burst has been Found that Actually Repeats Every 16 Days” Universe Today, 12 February 2020 <https://www.universetoday.com/144968/a-rare-fast-radio-burst-has-been-found-that-actually-repeats-every-16-days/>.