Is the Milky Way an ‘outlier’ galaxy?

A three-color optical image of a Milky Way sibling.
September 20, 2017

Yale Astronomy Professor Marla Geha’s SAGA survey indicates that the Milky Way galaxy may be unusual in its behavior, which is significant because many current models of the workings of the Universe rely on the Milky Way as a standard.

Early results from the Satellites Around Galactic Analogs (SAGA) Survey indicate that the Milky Way’s satellite galaxies are much more tranquil than other systems of comparable luminosity and environment. Many satellites of those “sibling” galaxies are actively pumping out new stars, but the Milky Way’s satellites are mostly inert, the researchers found.

SAGA researcher Risa Wechsler, an astrophysicist at the Kavli Institute at Stanford University, said “The SAGA Survey will provide a critical new understanding of galaxy formation and of the nature of dark matter.”

Geha is the lead author of the paper discussing the results, which appears in the Astrophysical Journal.

This article has been adapted from a Yale University Press Release by Jim Shelton.

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