Scientists have discovered a massive galaxy cluster deep in space that has a core bursting with baby stars. The findings, which were made using the W.M. Keck Observatory's MOSFIRE instrument, are the first to show that enormous galaxies at the center of clusters can grow by feeding of gas "stolen" from other galaxies, the University of California, Riverside reported.
"It is very exciting to have discovered such an interesting object," said Gillian Wilson, a professor of physics and astronomy at Cal-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."
Galaxy clusters are rare regions of the universe in which hundreds of galaxies brimming with stars and hot gas reside. Galaxies at the centers of these clusters, dubbed Brightest Cluster Galaxies (BCGs), are the largest known to science. The newly discovered object, called "1049+56,″ could help shed light on how these galaxies got so big.
"What is so unusual about this cluster, SpARCS1049+56, is that it is forming stars at a prodigious rate, more than 800 solar masses per year," Wilson said. "To put that in perspective, our own galaxy, the Milky Way, is forming stars at the rate of only about one solar mass per year."
The recent findings showed SpARCS1049+56 contains at least 27 galaxies and has a total mass equal to about 400 trillion Suns. The observations also revealed a "beads on a string" formation composed of clumps of new star formations on filaments of hydrogen gas. This phenomenon suggests the occurrence of a "wet merger" in which one galaxy in a galactic collision is gas-rich, and the gas is converted into new stars. The "beads on a string" feature in the core of SpARCS1049+56 are most likely caused by the BCG in the process of devouring a gas-rich spiral galaxy.
"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 said.
The findings were published in a recent edition of the Astrophysical Journal.
