It existed about 400 million years after the big bang, 13.8 billion years ago, the researchers estimated.
The team has nicknamed the object Tayna, which means "first-born" in Aymara, a language spoken in the Andes and Altiplano regions of South America.
Though Hubble and Spitzer have detected other galaxies that are record-breakers for distance, this object represents a smaller, fainter class of newly-forming galaxies that until now have largely evaded detection.
These very dim objects may be more representative of the early universe, and offer new insight on the formation and evolution of the first galaxies.
"Thanks to this detection, the team has been able to study for the first time the properties of extremely faint objects formed not long after the big bang," said lead author Leopoldo Infante, an astronomer at the Pontifical Catholic University of Chile.
The new object is comparable in size to the Large Magellanic Cloud (LMC), a diminutive satellite galaxy of our Milky Way, the study said.
The results were published in The Astrophysical Journal.
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