They’ve used the James Webb Space Telescope to study this early galaxy while also observing two neighbouring galaxies, which they name Firefly-Best Friend and Firefly-New Best Friend, located at 6,000 and 40,000 lightyears from Firefly Sparkle, respectively.
They found that Firefly Sparkle is one of the lowest-mass galaxies resolved into star clusters observed at cosmic dawn – when galaxies were starting to form – with a mass similar to that of a progenitor Milky Way. The researchers say continued study of these galaxies can provide clues on how the Milky Way formed.
First observed with the Hubble Space Telescope, new detailed observations from James Webb and presented by Lamiya Mowla and colleagues shed further light on the galaxy’s formation. The team used spectrometry and gravitational lensing – a phenomenon where a foreground massive object bends light from a distant source – to estimate that the galaxy is located at a redshift of 8.3, placing Firefly Sparkle in the first 600 million years of the Universe.
They indicate the mass of Firefly Sparkle is concentrated in 10 clusters of stars, with a total mass of approximately 10 million times that of our Sun. This makes Firefly Sparkle one of the lowest-mass galaxies resolved into star clusters observed at cosmic dawn, an epoch when galaxies were starting to form, with a mass similar to that of a progenitor Milky Way.
