New stellar streams confirm 'melting pot' history of the galaxy

ScienceDaily | 1/10/2018 | Staff
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Much like the waves of migration that brought diverse groups of people to the United States, our own Galaxy is thought to have been enriched by stars from other galaxies in discrete migration events. When a small neighboring galaxy ventures close to the Milky Way, the gravitational pull of the Milky Way draws out tendrils of stars from the neighboring galaxy, which trail behind it in a stream. Many such interactions are thought to have contributed stars to the halo of the Milky Way.

Eleven new stellar streams, discovered in data from the Dark Energy Survey (DES), were reported today in a special session held at the American Astronomical Society meeting in Washington, DC. Prior to the discovery, only two dozen or so stellar streams were known, many of which were discovered in data from a precursor survey, the Sloan Digital Sky Survey (SDSS).

DES - Data - Dwarf - Neighbors - Milky

DES data have been previously used to discover numerous dwarf galaxy neighbors of the Milky Way. While finding dwarf galaxies is a challenging endeavor -- they are faint and diffuse -- stellar streams are even more difficult to pick out, because their stars are spread out over a much larger area of sky. "These discoveries are possible because the Dark Energy Survey is the widest, deepest, and best-calibrated survey out there," explained Alex Drlica-Wagner (Fermilab), a member of the DES team.

Data from the first three years of the survey, which is being carried out with the Dark Energy Camera (DECam) on the 4-m Blanco telescope at CTIO, were also made publicly available in conjunction with the announcement.

DES - Nature - Energy - Thing - Survey

Although DES was carried out primarily to understand the nature of dark energy, "The great thing about a big astronomical survey like this is that it also opens a door to many other discoveries, like the new stellar streams," explained Adam Bolton,...
(Excerpt) Read more at: ScienceDaily
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