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(LEAD) S. Korean astronomers confirm existence of wandering globular clusters
SEOUL, March 12 (Yonhap) -- South Korean astronomers said Friday they have confirmed the existence of "wandering" globular clusters that can help advance understanding of the universe's birth.
The discovery marks the first time that scientists have provided evidence on the existence of wandering or intergalactic globular clusters made up of millions of stars, the team led by Lee Myung-gyoon, a professor at Seoul National University (SNU), said. | | Lee Myung-gyoon, professor of physics and astronomy, Seoul National University |
The research was published in the latest online issue of "Science Express" and will be carried by "Science Magazine" in about a month.
The clusters detected were within the Virgo Galaxy Cluster that lies 50-60 million light years away from Earth and is centered on the giant elliptical galaxy Messier 87. The Virgo group lies between the constellations Virgo and Coma Berenices that dominate the night sky in the northern hemisphere in spring.
Scientists have predicted 60 years ago that globular clusters that wander in space may exist, and for 20 years many have hypothesized that these masses of stars may be found in galaxy clusters. However, they have been unable to prove it because of the relatively "small" size of these bodies, which are not inside or very close to galaxies, and their sheer distance from Earth.
The clusters are significant because they may have been formed by small galaxies at the time of the Big Bang, and then were separated from their place of creation to wander the cosmos. Because they were not absorbed by larger galaxies, scientists speculated that these clusters may be made up of predominately older stars and consequently may be deficient in heavy elements like iron and gold, which are created by the merging of interstellar objects over long periods of time.
Lee, who teaches at the school of physics and astronomy, said his findings were possible because the Virgo Cluster is the nearest of the "big cluster of galaxies" that offers the best opportunities to find large objects. It is the first galaxy clusters discovered by scientists in the late 18th century and is roughly 10 million light years across.
He also said that while his team did not have access to large telescopes, they made full use of raw data from the U.S. Sloan Digital Sky Survey open material. The survey provides data on about a quarter of the sky seen from Earth. | | Globular Clusters |
"The data we looked at was raw, but by incorporating a system to cross-reference brightness, color and size of specks of light that are not part of the 1300-plus galaxies in the Virgo group, we have found around 1,500 wandering globular clusters," he said.
This is about 13-15 percent of the wandering globular clusters that may actually be in the galaxy group.
"There was skepticism from some reviewers at first, but the detailed evidence we were able to produce allayed doubts," Lee claimed.
He added that his team was fortunate to be the first to make the discovery since many scientists, using their own high-powered telescopes, may be close to providing similar evidence.
"Additional discoveries that may actually be more detailed should be announced in one or two years," he said.
The SNU professor, meanwhile, said that his team needs to do research to provide details on the initial discovery and determine the age, weight and elements in these wandering clusters.
The research conducted for the past three years was funded by the Ministry of Education, Science and Technology and the National Research Foundation of Korea.
yonngong@yna.co.kr
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