Galaxy Cluster MACS J1423, nicknamed Firefly Sparkle. Image: © NASA, ESA, CSA, STScI, Chris Willott, Lamiya Mowla, Kartheik Iyer
Dr Lamiya Mowla, who spotted the galaxy, was drawn to its gleaming star clusters, hence the nickname Firefly Sparkle.
NASA’s James Webb Space Telescope has found a galaxy from the universe’s early stages that gives scientists an idea of what our Milky Way would have looked like and “weighed” at that stage of development.
Scientists captured images of the galaxy cluster MACS J1423, nicknamed Firefly Sparkle, as it appeared 600m years after the Big Bang. The imaging shows that the galaxy has 10 star clusters compared to the Milky Way’s around 150.
Firefly Sparkle, falling into the category of low-mass galaxies, is currently in the process of assembling and will take billions of years before it takes its full shape. According to pre-existing research, it is predicted that galaxies in the early universe form through interactions and mergers with tinier galaxies.
The young galaxy is only 6,500 light years from its first companion and 42,000 light years from its second. In comparison, the fully formed Milky Way is 100,000 light years across and could easily fit Firefly Sparkle and its companion galaxies inside it.
“I didn’t think it would be possible to resolve a galaxy that existed so early in the universe into so many distinct components, let alone find that its mass is similar to our own galaxy’s when it was in the process of forming,” said Dr Lamiya Mowla, co-lead author of the study published in Nature and an assistant professor at Wellesley College in Massachusetts.
“Most of the other galaxies Webb has shown us aren’t magnified or stretched, and we are not able to see their ‘building blocks’ separately. With Firefly Sparkle, we are witnessing a galaxy being assembled brick by brick.”
Scientists also found that Firefly Sparkle’s star clusters did not form all at once, instead, their formations were staggered in time.
“This galaxy has a diverse population of star clusters, and it is remarkable that we can see them separately at such an early age of the universe,” said Dr Chris Willott from the National Research Council of Canada’s Herzberg Astronomy and Astrophysics Research Centre, a co-author of the study and the observation program’s principal investigator.
“Each clump of stars is undergoing a different phase of formation or evolution.”
According to researchers, the gravitational lensing – or the phenomenon when a massive galaxy cluster causes curvature in spacetime – as well as the James Webb’s specialisation in infrared light allowed them to observe and capture Firefly Sparkle’s images in “crisp” detail.
“Without the benefit of this gravitational lens, we would not be able to resolve this galaxy,” said Dr Kartheik Iyer, co-lead author and NASA Hubble Fellow at Columbia University in New York.
“We knew to expect it based on current physics, but it’s surprising that we actually saw it.”
Earlier this year, James Webb found a frenzy of activity in M82, a galaxy 12m light years away sprouting new stars 10 times faster than the Milky Way.
In 2022, the powerful telescope released its first colour images which showed the galaxy cluster SMACS 0723 as it appeared 4.6bn years ago.
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