Four previously unknown galaxy clusters, possibly containing thousands of galaxies were discovered 10 billion light years away from Earth by Imperial College London astronomers.
The discovery was made using a new way of combining data from the two European Space Agency satellites, Planck and Herschel. Using this new technique, researchers hope to discover more than 2000 new galaxies, giving them a better understanding of how galaxy clusters form.
The light from the most distant galaxy cluster reached earth in 10 billion light years. This discovery allows researchers to see what galaxy clusters looked like when the universe was only 3 billion years old.
"Although we're able to see individual galaxies that go further back in time, up to now, the most distant clusters found by astronomers date back to when the universe was 4.5 billion years old," lead researcher Dr David Clements, from the Department of Physics at Imperial College London said in a statement. "This equates to around nine billion light years away. Our new approach has already found a cluster in existence much earlier than that, and we believe it has the potential to go even further."
Galaxy clusters are the most massive objects in the universe. They usually contain thousands of galaxies, bound together by gravity. To better understand how these clusters form, researchers need to go back in time and this can only be done by discovering clusters that are further away from the Earth. Researchers can identify clusters at huge distances from our planet because these clusters are filled with gas and dust and are constantly forming new stars. When the light emitted from these stars reaches the Earth, researchers identify the cluster and determine their distance.
This discovery was one of the first projects where researchers combined data from two satellites. Both these satellites ended their operations last year. The Planck satellite was used to scan the whole sky while the Herschel scanned certain sections of the sky in greater detail.
"The fantastic thing about Herschel-SPIRE is that we are able to scan very large areas of the sky with sufficient sensitivity and image sharpness that we can find these rare and exotic things. This result from Dr. Clements is exactly the kind of thing we were hoping to find with the HerMES survey," Seb Oliver, Head of the HerMES survey said in a statement.
Sixteen sources were identified by the researchers out of which most were confirmed as single nearby galaxies that were already known. Four were shown by Herschel to be formed of multiple, fainter sources, indicating previously unknown galaxy clusters, according to IB Times UK.
Galaxies are usually categorized into two types. Elliptical galaxies are those that have little gas and dust but many stars and spiral are those that have more stars but little dust and gas. Our Milky Way belongs to the second category. Scientists believe the galaxies within the newly discovered clusters are of the elliptical kind, which are in the process of being formed.
Findings on the new discovery were published in the Monthly Notices of the Royal Astronomical Society.
