Gigantic Galaxy Bursts With 800 New Stars Per Year

Astronomers have discovered a galaxy 9.8 billion light years away that creates an astounding 800 stars a year. The Milky Way produces two stars per year at most.

“It is very exciting to have discovered such an interesting object,” said Gillian Wilson, a professor of physics and astronomy at the University of California, Riverside and a member of the research team. “Understanding its nature proved to be a real scientific challenge which required the combined efforts of an international team of astronomers and many of the world’s best telescopes to solve.”

IN A GALAXY FAR, FAR AWAY

Galaxies exist within rare regions of the universe known as galaxy clusters. The largest ones are located at the cluster’s center, and are called Brightest Cluster Galaxies (BCGs).

The cluster named SpARCS1049+56 was first discovered using NASA’s Spitzer Space Telescope at the W. M. Keck Observatory in Hawaii. The Spitzer was used in combination with the Herschel Space Telescope to detect infrared light. Researchers learned that the cluster is 9.8 billion light years away, contains 27 galaxies, and has a total mass equal to 400 trillion Suns.

Scientists wanted to pin down where star formation was taking place so they brought in the Hubble Space Telescope. It showed ‘beads of string’ at the center SpARCS1049+56. This is an indication of a ‘wet merger,’ which occurs when at least one galaxy in a collision between galaxies is gas rich. The gas is then converted into stars.

Researchers believe that the BCG at the cluster’s center collided with a smaller gas-rich galaxy, igniting a monstrous production of new stars.

SHEDDING NEW LIGHT ON STAR FORMATION

“What is particularly interesting is that BCGs in clusters of galaxies closer to the Milky Way are thought to grow by so-called ‘dry mergers,’ collisions between gas-poor galaxies which do not result in the formation of new stars,” Wilson stated.

This is also one of the first to known cases of a ‘wet merger’ at the core of a galaxy cluster, and the farthest example ever observed.

Scientists will continue their research to determine if SpARCS1049+56 is a unique case, or if other galaxies are expanding in a similar way.


 

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