The extraordinary images - taken with NASA's James Webb Space Telescope - show a galaxy that glitters with 10 distinct star clusters that formed at different times, much like our own Milky Way.

Cocooned in a diffuse arc, and resembling fireflies "dancing" on a summer night, the newly discovered galaxy - which the Wellesley team have dubbed the "Firefly Sparkle" - was taking shape around 600 million years after the Big Bang, around the same time that our own galaxy was beginning to take shape.

Wellesley College astronomer Lamiya Mowla is co-lead author of the paper, which was published Wednesday, Dec. 11, in Nature.

Mowla says the discovery is particularly important because the mass of the Firefly Sparkle is similar to what the Milky Way's mass might have been at the same stage of development. (Other galaxies Webb has detected from this time period are significantly more massive.)

"These remarkable images give us an unprecedented picture of what our own galaxy might have looked like when it was being born," Mowla says. "By examining these photos of the Firefly Sparkle, we can better understand how our own Milky Way took shape."

Glimpses of a young galaxy forming in a way so similar to our own are unparalleled, Mowla says. The JWST images show a Milky Way-like galaxy in the early stages of its assembly in a universe that's only 600 million years old.

"As an observational astronomer studying the structural evolution of astronomical objects in the early Universe, I want to understand how the first stars, star clusters, galaxies, and galaxy clusters formed in the infant Universe and how they changed as the Universe got older," Mowla notes. Of the Firefly Sparkle, she says, "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.

"There is so much going on inside this tiny galaxy, including so many different phases of star formation," Mowla told NASA. "These images are the very first glimpse of something that we'll be able to study - and learn from - for many years to come."

Mowla, who co-led the project with Kartheik Iyer, a NASA Hubble Fellow at Columbia University in New York, is an assistant professor of physics and astronomy at Wellesley, and a 2013 graduate of the college.

Full Caption:

This horizontal image is split down the middle. At left is a galaxy cluster showing thousands of overlapping objects at various distances spread across this field. The background of space is black. The galaxies' colors vary. The majority appear white or pink, some are shades of orange or blue.

Most galaxies appear as fuzzy ovals, but a few have distinctive spiral arms. The most distant galaxies are the tiniest and appear as red dots or smudges. Several foreground stars with eight diffraction spikes appear as large as some of the smaller galaxies. Just above center is a very bright white, oversized oval, which is angled at 45 degrees, pointing to the top left and bottom right.

This is a supergiant elliptical galaxy. Immediately around it are many thin, long, orange or pink arcs. They follow invisible concentric circles that curve around the center. These are background galaxies that have been stretched and distorted.

To the bottom right of this supergiant elliptical galaxy is the white outline of a small box. On the right side is a zoomed in view of this area. There are two smaller dotted circles flanking a larger dotted oval at the center.

The central oval is labeled Firefly Sparkle galaxy. Within it appears a discontinuous, long line that roughly points from bottom left to top right. The Firefly Sparkle galaxy is a gravitationally lensed galaxy.

It contains 10 circular clusters of stars that are largely pink and purple toward the bottom left, with some larger circles that have blue centers toward the top. There are hazy, semi-transparent pink dots toward the top right with some hazy blue. Most of these star clusters appear joined by a faint, light blue line.

The galaxy to the bottom left is labeled Companion 1 and looks like a bright red dot, slightly larger and brighter than most in the Firefly Sparkle galaxy, with at least two far hazier, semi-transparent red dots to its left and right.

To the right, Companion 2 is lighter red overall, with the darkest area at the center forming a tiny oval, and a red disk extending on its left and right, giving it the appearance of an edge-on galaxy. Smaller hazy red dots appear to the top center and top right.

In the background, several dozen hazy galaxies appear in a range of sizes and shapes, most appearing far larger than the circled objects. They are light pink, dark pink, orange, and diffuse blue, and take on the shapes of circles and ovals.

Research Report:Formation of a low-mass galaxy from star clusters in a 600-million-year-old Universe

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