Previous to the discovery of the 11 new streams, just 23 other stellar streams have been found. The new streams are the faintest and most distant streams ever discovered.
“In general, these newly detected streams are wider and lower surface brightness than those detected in previous surveys,” the team wrote in their paper.
Alex Drlica-Wagner, a member of the DES team, said: “These discoveries are possible because the Dark Energy Survey is the widest, deepest, and best-calibrated survey out there.”
The streams provide important information about the history of the Milky Way’s formation and can be used to trace the local distribution of dark matter. The streams form when a small nearby galaxy or star cluster ventures too close to the Milky Way and the gravitational pull of our larger galaxy pulls out streams of stars from the wandering galaxy. Astronomers think that many interactions like these have contributed stars to the halo of the Milky Way.
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The new stellar streams have names such as Molonglo, Jhelum, Aliqa Uma, and Wambelong. The DES team reached out to schools in Chile and Australia and asked young students to select names. The names are aquatic words in native languages from northern Chile and aboriginal Australia.
Shipp and her colleagues wrote that they expect additional DES observations, improved data reduction techniques, and improved stream detection algorithms will allow fainter and more distant streams to be detected in the near future.
“While the DES data currently provide the most sensitive wide-area view of the southern sky,” the team wrote, “they are merely a precursor for larger sky coverage that can be achieved with DECam and, eventually, the Large Synoptic Survey Telescope.”
The LSST is currently under construction on Cerro Pachon in Chile.
“In the 2020s, LSST will deliver a yet wider and deeper view of the Universe — from distant galaxies, to our Milky Way, down to the solar system,” said Adam Bolton, associate director for the Community Science and Data Center at NOAO, “ and not just as a still photo, but as a high-definition movie that will capture the rich variability of the sky.”