The light from the distant Sparkler galaxy was
spotted in the James Webb Telescope's First Deep Field and could teach us how
our own Milky Way devoured other galaxies to grow.
Top image Description: An artist's impression of the
Milky Way in its youth, surrounded by globular clusters. (Image credit: James
Josephides, Swinburne University)
A sparkling cannibal galaxy discovered by the James
Webb Space Telescope appears to be a "very early" mirror image of the
Milky Way, and it could help astronomers understand how our galaxy took shape,
a new study has revealed.
Located 9 billion light-years from Earth, the galaxy
is named the "Sparkler" after the dwarf galaxies and two dozen
globular clusters — swarms of millions of stars bound together by gravity —
that shine around it. According to the study authors, the galaxy is voraciously
gorging upon these nearby objects to grow ever larger.
The cosmic feeding frenzy was discovered in Webb's
First Deep Field — the deepest and most detailed view of the universe ever
captured, and the James Webb Space Telescope's (JWST) first full-color picture.
Released in July 2022, the image shows the Sparkler galaxy as a warped orange
line surrounded by spots of light. Now, an analysis published Dec. 26 in the
journal Monthly Notices of the Royal Astronomical Society (link at the bottom)
has revealed that the galaxy is growing by cannibalizing its neighbors — much
like the young Milky Way is thought to have done.
"We appear to be witnessing, first hand, the
assembly of this galaxy as it builds up its mass—in the form of a dwarf galaxy
and several globular clusters," lead-author Duncan Forbes(opens in new tab),
a professor of astrophysics at Swinburne University of Technology, Australia,
said in a statement. "We are excited by this unique opportunity to study
both the formation of globular clusters, and an infant Milky Way, at a time
when the universe was only one-third of its present age."
Twinkling from within the Volans constellation in
the southern sky, the distant Sparkler's light took 9 billion years to travel
to us; arriving at the James Webb Space Telescope after the space-time warping
gravitational pull of the galaxy cluster SMACS 0723 acted as a gigantic lens to
steer it into focus.
The Webb's First Deep Field is the deepest and
sharpest infrared image of the distant universe to date. (Image credit: NASA, ESA, CSA, and STScI)
This travel time means that the light reveals the
galaxy as it was just 4 billion years after the Big Bang. At this point in our
universe's ancient history, the Sparkler was just 3% of the Milky Way's mass,
but in the present day, scientists expect that the ravenous giant has stuffed
itself to match the size of our own galaxy.
Scientists think this because they observed some key
resemblances between the Sparkler and our own Milky Way. By analyzing the
globular clusters that surround the Sparkler, the scientists discovered that
star swarms resemble younger versions of the roughly 200 globular clusters
spotted around the Milky Way. And the Sparkler's active consumption of a nearby
dwarf galaxy is another notable parallel to our galaxy's monstrous past — the
evidence for which we see in the remnant trails of stars and clusters from
shredded galaxies strewn outside our galactic disc.
Scientists are still unsure how stars came to clump
into globular clusters, but the Sparkler offers a glimpse of the cosmic enigmas
when they were young.
"The origin of globular clusters is a
long-standing mystery, and we are thrilled that JWST can look back in time to
see them in their youth," co-author Aaron Romanowsky, a professor of
astronomy at San Jose State University, California, said in the statement.
With the Sparkler's resemblance to our own galaxy
clearly established, the researchers now want to use deeper imaging to spot
more clusters around the distant galaxy and learn even more about how both it
and our own galaxy came to be.
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