Astronomers Discover a Galaxy Cluster Exploding New Stars at its Core
In a significantly rare discovery, astronomers have located a galaxy cluster that is bursting with new stars at its center using NASA and the Hubble space telescopes. The discovery lends credence to the theory that massive galaxies located at the cores of these tremendous clusters can grow substantially by absorbing the gas taken from another nearby galaxy.
Astronomers, with the borrowed help of NASA’s Spitzer telescope and the Hubble space telescope, have discovered a unique gargantuan galaxy cluster. Unique, due to its core birthing new stars – right in the middle of the galaxy cluster, reports NASA’s Jet Propulsion Laboratory.
The finding is published in a paper titled “An Extreme Starburst In The Core Of a Rich Galaxy Cluster At z = 1.7”, accepted by The Astrophysical Journal.
Tracy Webb from McGill University, Montreal, Canada and lead author of the new paper said:
We think the giant galaxy at the center of this cluster is furiously making new stars after merging with a smaller galaxy.
Massive Galaxy Clusters
Galaxy clusters are essentially massive swarms or families of galaxies bound together by gravity. Our galaxy, the Milky Way, is located in a small galaxy group called the Local Group. The Local Group is a member of the dizzyingly vast Laniakea (Hawaiian for “immeasurable heaven) supercluster that comprises of a 100,000 galaxies.
The newly discovered cluster, codenamed ‘SpARCS1049+56’ by the astronomers has at least 27 known galaxy members and a staggering combined mass equal to that of 400 trillion suns. The cluster is located 9.8 billion light-years away from the earth, in the Ursa Major constellation.
Astronomers initially made the discovery using the Spitzer and the Canada-France-Hawaii telescope installed on Mauna Kea in Hawaii. The confirmation of the galaxy cluster occurred at the W.M. Keck Observatory, also located on Mauna Kea.
The Galaxy Cluster Birthing New Stars at its Heart
The core of most massive galaxy clusters contains one mammoth galaxy that does not tend to produce stars quickly. The newly found galaxy cluster has a galaxy at its core that is churning out an enormous number of stars, about 860 new ones a year. In stark contrast, our Milky Way produces only about one or two new stars per year. This phenomenon of rapid generation of new stars at its core is what makes SpARCS1049+56 unique.
Usually, the stars at the centers of galaxy clusters are old and dead, essentially fossils, explains Tracy Webb.
“The Spitzer data showed us a truly enormous amount of star formation in the heart of this cluster, something that has rarely been seen before, and certainly not in a cluster this distant,”she added.
Jason Surace from NASA’s Spitzer Science Center in Pasadena, California points to the fact that the Spitzer telescope detects infrared light that offers visibility of the warm glow of dusty regions where stars are born.
“With Spitzer’s infrared camera, we can actually see the ferocious heat from all these hot young stars,” said Spurce, who also co-authored the paper.
To follow-up on the discovery, astronomers used the Hubble Telescope in visible light to look into the source of fuel forming the new stars. They discovered a small galaxy that recently merged with the mammoth galaxy in the middle of the cluster, proving its gas to the larger galaxy that sparked the birth of new stars.
Hubble found a train wreck of a merger at the center of this galaxy, said Webb.
The astronomers and researchers plan to do more studies to see if galaxy clusters such as SpARCS1049+56 are a common phenomenon. At the very least, it may be a marker, showing us the likelihood of earlier times in our Universe when swallowing gas-rich galaxies by other bigger galaxies was of the norm.
Images from Shutterstock, Wikimedia and NASA.