Fast radio bursts (FRBs) have always fascinated — not to mention befuddled — the astronomy community since they were discovered a decade ago. The fact that astronomers cannot determine what causes them to appear and where they come from have added to their mystery.
Fast radio bursts are bright, fleeting radio pulses that can be observed from the skies and last about a millisecond. There are now 18 known FRBs detected through single-dish radio telescopes. Scientists have not been able to narrow down and identify the exact location and galaxies of these FRBs, up until now.
Some of the mysteries surrounding this phenomenon have been answered after a group of astronomers have traced one of these fast radio bursts back to its home galaxy.
FRB 121102: A Recurring Phenomenon In The Sky
One FRB in particular has stood out among all the other FRBs detected by astronomers. The FRB 121102 — named after the date of its first burst — was discovered at the Arecibo Observatory in Puerto Rico. What's fascinating about this FRB is that it has recurred a couple of times, allowing observers to establish a pattern.
Astronomers watched out for the recurring FRB this year using a very special equipment: the Karl G. Jansky Very Large Array (VLA) system. This advanced radio telescope system has the ability to see finer details and pinpoint an object's exact location in the sky. The VLA detected a total of nine bursts from FRB 121102 in a span of six months in 2016.
Surprising Result: FRB Came From Dwarf Galaxy, Not A Large Galaxy
In theory, scientists expect FRBs to come from large galaxies where there are a lot of stars, including neutron stars that emit electromagnetic radiation beams, known as pulsars.
But now it appears this is not the case as an astronomy group headed by McGill University researcher Shriharsh Tendulkar found out that the FRB 121102 did not come from a large galaxy; but rather, it comes from a dwarf galaxy three billion light years away. "The host galaxy for this FRB appears to be a very humble and unassuming dwarf galaxy, which is less than 1% of the mass or our Milky Way galaxy. That's surprising. One would generally expect most FRBs to come from large galaxies," says Tendulkar.
According to Tendulkar, the reason behind the FRBs could be due to "long duration gamma-ray bursts and superluminous supernovae," two events that frequently happen in dwarf galaxies.