Monstrous Galaxy Cluster Cannibalizes Itself to Create New Stars

October 2, 2015 | Sarah Tse

This image, using data from Spitzer and the Hubble Space Telescope, shows the galaxy cluster SpARCS1049.
Photo credit: NASA/STScI/ESA/JPL-Caltech/McGill (CC by 3.0)

Astronomers have spotted a new galaxy cluster that’s gushing with new stars, fueled by gorging its own galaxies.

A newly discovered galaxy cluster of epic proportions has puzzled scientists with its bizarre behavior. A team of international astronomers used the Hubble and Spitzer Telescopes to examine the cluster, finding that the largest galaxy is slowly devouring the galaxies around it. This gluttonous behavior has fueled a burst of star-forming activity in the galaxy.

Galaxy clusters are made up of hundreds to thousands of galaxies held together by gravity. At the very center of a cluster, you’ll usually find the largest, oldest, dullest galaxy that’s little more than a cemetery of dead or dying stars. But the cluster named SpARCS1049+56 has a surprisingly lively core that’s pumping out fresh stars like a photocopier on steroids. While the Milky Way is lucky to create two new stars per year, this hulk of a galactic factory belches out more than 800 new stars each year!

SEE ALSO: Twin Supermassive Black Holes on Verge of Collision

Scientists first spotted the galaxy using infrared data from the Spitzer Telescope, which revealed the heat being emitted by each new starbirth. When the scientists used the Hubble Telescope to get a closer look at the galaxy cluster’s visible light emissions, they realized that the central galaxy owed its vigor to a smaller galaxy that it had recently gobbled up. This transfusion of stellar gas, known as a “wet merger,” stimulated the monster galaxy into an episode of hyperactivity. These hot young stars formed so rapidly that they grouped together in a chain, creating a cosmic characteristic known as “beads on a string.”

This is the first time astronomers have spotted a wet merger of galaxies at the center of a cluster this huge and distant. Astronomers had discovered a wet merger in a galaxy cluster closer to home, but it wasn’t nearly as productive of a star factory as this new discovery is. Other instances of galaxy fusion are called “dry mergers” when there isn’t enough gas to kickstart star formation.

SpARCS1049+56 contains at least 27 galaxies with the combined mass of 400 trillion Suns. It’s also so far away that we’ve only just received the light it emitted 9.8 billion years ago. Scientists now wonder if this galaxy’s gluttonous behavior is simply an artifact of an earlier time in the universe. Further research will reveal whether this galaxy’s growth method is truly an anomaly, or if we’re just looking at an immature cluster that hasn’t yet learned its manners.

Hot Topics

Facebook comments