A galaxy 11.3 billion light-years away appears filled with dark matter
The finding bucks earlier research suggesting faraway galaxies lack the invisible stuff
BY LISA GROSSMAN 8:00AM, AUGUST 17, 2018
LONG AGO AND FAR AWAY Using the telescopes of the Atacama Large Millimeter/submillimeter Array in Chile (shown), astronomers discovered the most distant yet galaxy that appears to be filled with dark matter.
A distant galaxy appears filled with dark matter.
The outermost stars in the Cosmic Seagull, a galaxy 11.3 billion light-years away, race too fast to be propelled by the gravity of the galaxy’s gas and stars alone. Instead, they move as if urged on by an invisible force, indicating the hidden presence of dark matter, astrophysicist Verónica Motta of the University of Valparaíso in Chile and her colleagues report August 8 at arXiv.org.
“In our nearby universe, you see these halos of dark matter around galaxies like ours,” Motta says. “So we should expect that in the past, that halo was there, too.”
Motta and her colleagues used radio telescopes at the Atacama Large Millimeter/submillimeter Array (ALMA) to measure the speed of gas across the Cosmic Seagull’s disk, from the center out to about 9,800 light-years. They found that the galaxy’s stars speed up as they get farther from the galaxy’s center.
More:
https://www.sciencenews.org/article/galaxy-113-billion-light-years-away-appears-filled-dark-matter