The mystery of fast radio bursts (FRBs) has deepened with the discovery of FRB 20190208A, traced to a faint dwarf galaxy more than halfway across the observable Universe. This finding challenges existing assumptions about FRB origins, as most are linked to massive, star-forming galaxies.

“The majority of fast radio burst host galaxies seem to be massive, star-forming galaxies – perhaps implying that most FRBs are produced by magnetars formed from core collapse supernovae,” said astronomer Danté Hewitt.

“However, the faintness of the FRB 20190208A host galaxy implies that it’s one of the least massive FRB host galaxies we’ve ever seen – so that was definitely surprising!”

FRBs are intense, millisecond-long radio wave bursts releasing energy equivalent to 500 million Suns. While most are one-off events, some, like FRB 20190208A, repeat, making them easier to study.

Detected in February 2019, this repeating FRB was observed for 65.6 hours between 2021 and 2023, during which it burst twice more. Using radio and optical telescopes, astronomers pinpointed its origin to a faint dwarf galaxy.

“Our initial attempts at identifying a host galaxy revealed no source at the FRB position. We were a little baffled,” Hewitt said.

“But then, when we saw the images from the Gran Telescopio Canarias, there was a very exciting ‘Oh wow! Look! There’s actually a faint smudge right where the bursts are coming from’ moment.”

The galaxy’s faintness made distance measurement challenging, but the FRB’s dispersion suggests a light travel time of about 7 billion years, making it one of the most distant FRBs detected.

“This host galaxy is most likely 10-100 times fainter than the vast majority of other FRB host galaxies, perhaps on par with the Magellanic Clouds,” Hewitt noted. Dwarf galaxies, with their low metallicity, are known to host massive stars that end in core-collapse supernovae, leaving behind magnetars.

“Finding repeating FRB sources in dwarf galaxies thus potentially links these repeating FRB sources with massive star progenitors,” Hewitt explained.

“It’s a little poetic. When the most massive stars die, they unleash some of the most energetic explosions in the Universe; and then maybe, the remnants of those explosions continue to scream into the void, repeatedly producing FRBs.”

This discovery highlights the need for precise radio arrays and deep optical imaging to robustly associate FRBs with host galaxies.

“The story of FRB 20190208A tells us that in order to robustly associate an FRB with a host galaxy, we will sometimes need both a very precise position from radio arrays, as well as very deep imaging using the largest optical telescopes we currently have at our disposal,” Hewitt said.

While the mystery of FRBs remains unsolved, findings like these bring us closer to understanding these cosmic phenomena.

Adblock test (Why?)