While galaxies seem like lonely wanderers within the vast universe, many actually huddle closely in clusters, held together by their collective gravity. And sometimes, it will appear, in addition they munch on each other.
In other words, larger galaxies in these pockets merge with and gobble smaller ones to grow even larger — our own Milky Way galaxy actually cannibalized a small neighbor galaxy and gained supremacy about 10 billion years ago.
As for what happens to the smaller galaxies getting shredded by their massive counterparts? Well, while few disappear and not using a trace,, recent research shows that some tiny galaxies are dense enough to power through. Those mighty realms are in a position to hold onto their cores and develop into what astronomers call Ultra Compact Dwarfs, or UCDs.
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Using the Gemini North Telescope positioned near the Mauna Kea mountain in Hawaii, the team behind the research spotted galactic cannibalism in motion near the Virgo Cluster, a big grouping of 1000’s of galaxies relatively nearby to Earth. And in a primary, the researchers found small galaxy victims transitioning into UCDs. As many as 106 galaxies exhibited far-reaching envelopes of stars, suggesting their outer layers were being ripped apart by nearby large galaxies. Meanwhile, nevertheless, tight groupings of stars of their centers reveal their gravitational grip is robust enough to survive the merger, astronomers say.
After stars and gas within the galaxies’ outer layers are pried out in full, astronomers expect the tiny galaxies will come to represent late-stage UCDs.
“It’s exciting that we are able to finally see this transformation in motion,” Eric Peng, an astronomer at National Optical-Infrared Astronomy Research Laboratory, said in a statement. “It tells us that a lot of these UCDs are visible fossil remnants of ancient dwarf galaxies in galaxy clusters, and our results suggest that there are likely many more low-mass remnants to be found.”
Peng and his colleagues first spotted these candidate UCD progenitors in images taken by the Canada–France–Hawaii Telescope, also positioned near the summit of Hawaii’s Mauna Kea mountain. Nevertheless, in those images, it was very difficult to obviously distinguish the goal galaxies from other faraway galaxies beyond the Virgo Cluster, in keeping with the brand new study.
So, the team used Gemini North to perform follow up observations to accurately measure galaxy distances, then removed all background galaxies such that only the candidate UCDs throughout the Virgo Cluster could possibly be seen.
The outcomes showed these UCDs resided “almost exclusively near the most important galaxies,” Kaixiang Wang, the study’s lead creator and a scientist at Peking University in China, said within the statement. “We immediately knew that environmental transformation needed to be essential.”
This research is described in a paper published Wednesday (Nov. 8) within the journal Nature.