Observations of the tiny Sparkler dwarf galaxy have revealed that it is embedded in a system of ancient star clusters and eagerly feasts on its smaller galactic companions to grow.
This means that the galaxywhich was discovered in the first data of the James Webb Space Telescope (JWST), resembles early cannibals Milky Way which also grew by feeding on smaller galaxies. Thus, the study of this galaxy offers astronomers a unique insight into the evolution of the Milky Way.
The Magic Sparklerlocated in the southern constellation of Volens, owes its name to the fact that it is surrounded by about two dozen globular clusters, tight clusters of ancient stars. Each of these clusters could contain about a million stars. Our galaxy currently hosts about 200 globular clusters.
Related: 12 Amazing James Webb Space Telescope Discoveries Across The Universe
The team, led by Duncan Forbes, a professor at Swinburne University, and Aaron Romanowsky, a professor at San Jose State University, examined the age of Sparkler and its surroundings by examining the abundance of elements heavier than hydrogen and helium. Astronomers call these heavy elements “metals”.
Looking at the galaxy’s surrounding compact star clusters, they realized they looked like younger versions of the clusters around the Milky Way. Many are rich in metals, similar to the globular clusters in the central bulge of our galaxy. The researchers also observed mid-age, metal-poor clusters that are associated with a satellite galaxy that Sparkler is engulfing, with its globular clusters acting as a desert.
The Sparkler galaxy is currently only 3% of the mass of our galaxy, but researchers expect it to grow via this feeding process on cosmic time scales to eventually match the mass of the Way. milky way as we see it today.
“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,” Forbes said. in a report (opens in a new tab). “We are excited about this unique opportunity to study both the formation of globular clusters and an infant Milky Way, at a time when the Universe was only 1/3 of its current age.”
Go back in time with Einstein’s help
The Sparkler galaxy is located 9 billion Light years from Earth, which astronomers see as it was about 4 billion years after the big Bang. The observations are possible thanks to the impressive infrared observing power of the JWST and a phenomenon first predicted by Albert Einstein in 1915.
The great physicist general relativity theory suggests that objects of great mass “deform” the fabric of space like a heavy ball placed on a stretched sheet of rubber. Just as with this simple analogy, the larger the mass, the more extreme the curve it causes.
This means extremely massive objects like black holes or galaxies can “bump” space enough to distort light as it passes through them. Therefore, if light from a background object passes this distortion, its travel time is affected. This can lead to this background object being amplified by this foreground landing object, which is described as a “gravitational lens”.
The Sparkler galaxy is illuminated by such a gravitational lens that allows the JWST to spot its light that has been traveling for 9 billion years to reach the mighty space telescope.
The team will continue to study the globular clusters around Sparkler to learn more about this distant, ancient galaxy, and in turn our own galaxy, the Milky Way, and its evolution.
“The origin of globular clusters is a long-standing mystery, and we’re thrilled that JWST can look back in time to see them in their youth,” Romanowsky said.
The team’s research is published in the journal Royal Astronomical Society Monthly Notices (opens in a new tab)
Follow us on twitter @Spacedotcom Or on Facebook.