|Microwave image of the Phoenix Cluster. A research team, headed up by Kingston native Michael McDonald, has discovered a galaxy cluster 5.7 billion light years away with the ability to reproduce stars unusually quickly. (Photo courtesy Chandra X-Ray Observatory)
KINGSTON, Ont. – A group of astronomers have discovered an unusual cluster of far-away galaxies, and a Kingston, Ont., native is heading up the research team.
The team found a galaxy cluster 5.7 billion light years away with the ability to reproduce stars unusually quickly.
The team calls the new cluster they identified the “Phoenix Cluster” based on its unique properties. It contains hundreds of thousands of galaxies, and is about 2,500 trillion times the mass of the sun.
The largest galaxy in the cluster, the central galaxy, has been found to form 740 new stars a year. In comparison, the Milky Way forms only one new star in the same period of time.
Because of its age, it should have stopped creating new stars altogether billions of years ago. Yet this cluster continues to reproduce, which surprised the researchers.
“The fact that this one is still forming new stars is an anomaly. There's very few things like it in the universe,” said Michael McDonald, the team's leader, who was born and raised in Kingston and received both his bachelor's and master's degrees from Queen's University,
McDonald is now a Hubble Fellow at Massachusetts Institute of Technology's Kavli Institute for Astrophysics and Space Research.
His team discovered the cluster in 2010, but it took some time for them to gather enough data to understand its significance. It is one of the biggest identified clusters on record.
It's also the brightest. It's so hot that its light is measured in X-rays. Research done by the team shows it's the brightest cluster discovered so far in the universe.
And they believe its brightness is linked with the central galaxy's ability to reproduce new stars. The light stems from cool gas in the galaxy.
“Gas, if it cools enough, it can provide fuel for stars,” McDonald said. “Stars form out of cold gas. So rapid cooling should lead to new stars.”
In order to make the discovery and gather data, the team used 10 telescopes that were located both on the Earth and in space. NASA allowed the team to use three of its telescopes for the project, including the Chandra X-Ray.
McDonald said this discovery allows scientists to better understand how stars are formed.
It used to be thought that massive galaxies formed by absorbing other galaxies until they got bigger and bigger, he said. But this research is showing otherwise.
“This one seems to be growing just by consuming cool gas and converting that into stars. So it's not merging with galaxies at all,” he said. “It wasn't really thought this is the way a galaxy can grow and it looks like it is — in this one case, at least.”
These findings were published Wednesday in the journal Nature.