Astronomers witness birth of massive galaxy cluster
Michael d'Estries
April 26, 2018, 5:32 p.m.
Billions of years ago, well before our own solar system was born, 14 star-dense galaxies collided dramatically to form what astronomers now believe is likely "one of the most massive structures in the modern universe." Located some 12.4 billion light-years away, the so-called "birth of a protocluster core" appears today as it existed only 1.4 billion years after the Big Bang.
The astronomers made the remarkable discovery, detailed in the most recent issue of the journal Nature, after following up on the presence of a bright "fuzzy blob" in the night sky captured by South Pole Telescope in Antarctica. What they initially suspected was three galaxies turned out to be something much more dramatic when surveyed using the more sensitive Atacama Large Millimeter/submillimeter Array (ALMA) in Chile.
"It just hit you in the face because all of a sudden there are all these galaxies there," astrophysicist and study co-author Scott Chapman of Dalhousie University in Halifax, Canada, said in a statement. "We went from three to 14 in one fell swoop. It instantly became obvious this was a very interesting, massive structure forming and not just a flash in the pan."
While astronomers have observed massive clusters in the modern universe before, this is the first time they've captured one on the verge of forming. The statistics — as you might expect for 14 galaxies merging into one — are staggering. According to the researchers, the observed protocluster likely contained around 10 trillion suns’ worth of mass, growing to more than 1,000 trillion suns' worth of mass as it matured into one giant elliptical galaxy over billions of years.
In an interview with the BBC, co-author Dr. Axel Weiß of the Max Planck Institute for Radio Astronomy shared how all of this drama is unfolding in a region of space only four or five times the size of our own Milky Way galaxy.
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more: https://www.mnn.com/earth-matters/space/blogs/massive-galaxy-cluster-formation-detected-first-time
