In a galaxy not too far away, a record recently was broken — the densest galaxy known to man was discovered by an MSU assistant professor of physics and astronomy with the help of a team of astronomers.
Jay Strader first noticed a large spot in a Hubble Space Telescope photo two years ago and decided to find out whether it was a background galaxy — one that’s very far away — or a relatively nearby dwarf galaxy, he said.
The team used spectroscopy, which shows how far away an object is, to determine that it is a relatively close and small galaxy.
The large spot is now recognized as an ultra-compact dwarf galaxy and known as M60-UCD1. It is so dense that the distance between our sun and the nearest star — about four light years — is filled with about 10,000 stars. It has about 200 million stars, Strader said.
“Just looking at it doesn’t tell you that information,” Strader said of the location.
He added that anyone could have discovered it, but instead ignored it as a large and very far away galaxy.
Strader is working on finding out why it’s so dense; one theory is that it was once larger, but when it fell into the gravitation pull of a much larger galaxy, known as M60, all of its outer stars were pulled away, leaving the densest area.
Both the new galaxy and M60 are located in what could be a city of galaxies known as the Virgo Cluster, which is the nearest cluster to the Milky Way, said Anil Seth, who worked with Strader on the research and is a University of Utah assistant professor of physics and astronomy.
But humans won’t be going to visit any time soon.
“It’s extraordinarily far away from us — 50 million light years,” Strader said.
Still, it is so far away it’s considered to be in the local universe because advanced telescopes can see billions of light years away, Seth said.
The team of astronomers working on this also think that there is a black hole at the center, which could suggest that all dwarf galaxies have black holes.
Currently, black holes are expected to only be in larger galaxies, Strader said.
Seth said he’s most excited about the black hole aspect of the discovery and future research that he and Strader will conduct.
If they can confirm that there is a black hole, it could have implications about how black holes were formed in the early universe and how common they are, he added.
Stephen Zepf, associate chair for astronomy in the MSU Department of Physics and Astronomy, said he’s not surprised that Strader, who hasn’t been at MSU long, is conducting exciting research.
“It’s an example that we’re able to recruit and hire people who do groundbreaking work in their field,” he said. “We were excited to hire him, but we’re not surprised that he’s doing exciting and interesting things.”
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