Scientists examining an exhaustive survey of roughly 400 million objects in the cosmos have discovered incredible new insight on the violent ‘eating’ habits of the Milky Way.
Preliminary results from the Dark Energy survey have revealed a stunning look at the remains of 11 smaller galaxies that have been devoured by our own, reducing them to stellar streams.
As these objects are typically very difficult to spot, scientists say the most recent find could pave the way for other important discoveries about our universe – such as narrowing down the properties of dark matter.
Before the new discovery, only about two dozen stellar streams had been spotted.
The latest research relies on the first three years of data from the Dark Energy Survey, accounting for one-eighth of the entire sky, or about 5,000 square degrees.
More than 400 researchers from all around the world collaborated on the massive effort to reveal the nature of mysterious dark energy, using the Dark Energy Camera mounted on the NSF’s 4-meter Blanco telescope in Chile.
The current survey so far includes about 40,000 exposures taken with the camera.
‘There are all kinds of discoveries waiting to be found in the data,’ said Brian Yannay of Fermi National Accelerator Laboratory, Dark Energy Survey data management project scientist.
‘While DES scientists are focused on using it to learn about dark energy, we wanted to enable astronomers to explore these images in new ways, to improve our understanding of the universe.’
Through the survey, the researchers discovered 11 new stellar streams – the remnants of galaxies ripped to shreds by the Milky Way.
These objects are created as the Milky Way’s ‘halo’ of dark matter tugs on smaller nearby galaxies, pulling them in and effectively ripping them apart.
The Milky Way absorbs the smaller systems, leaving behind streams of sparsely scattered stars.
‘It’s exciting that we found so many stellar streams,’ said astrophysicist Alex Drlica-Wagner of Fermilab and the Kavli Institute for Cosmological Physics at UChicago.
‘We can use thse streams to measure the amount, distribution, and “clumpiness” of dark matter in the Milky Way.
‘Studies of stellar streams will help constrain the fundamental properties of dark matter.’
The team is working with schools in Chile and Australia to come up with names for the new streams, with plans to name them for aquatic words in native languages.
‘We’re interested in these streams because they teach us about the formation and structure of the Milky Way and its dark matter halo,’ said Shipp.
‘Stellar steams give us a snapshot of a large galaxy being built out of smaller ones.
‘These discoveries are possible because ES is the widest, deepest and best-calibrated survey out there.’
