A burst from a ‘blob’
FAST RADIO BURSTS (FRBs) were first discovered in 2007 and have vexed astronomers ever since. As the name implies, they’re fast (on the order of a millisecond) flashes of energy observed in radio waves. Now, a recently described
FRB that lies 9 billion light-years away could give astronomers an assist in tracing their origins.
Not only is it the farthest FRB spotted to date, but it’s one of the most unusual. That’s because the Very Large Telescope in
Chile showed not a well-defined host galaxy, but a blob. “We had never seen something that was so blobby looking,” says Northwestern University graduate student and study leader Alexa Gordon, who presented the work Jan. 9 at the winter meeting of the American Astronomical Society in New Orleans. “We weren’t sure if this was just a really sort of amorphous bizarre galaxy or if there were maybe multiple galaxies, interacting or merging.”
The team was awarded observing time on the Hubble Space
Telescope. This revealed that the blob consists of one large dwarf galaxy surrounded by six smaller dwarf galaxies, all packed into a space the size of the Milky
Way and likely to merge into one galaxy. The FRB, named
FRB 20220610A, is the first to have been found in such a compact group of merging galaxies.
The find gives a boost to the leading theory to explain FRBs, which is that they come from magnetars — highly magnetic, fast-spinning neutron stars. A neutron star is the ultra-compact husk of a large star that exploded into a supernova. “If we think FRBs come from magnetars, they should be connected to recent star formation,” Gordon says. And merging galaxies trigger star formation, giving the idea credence.