Ghostly Galaxies as Solitons of Bose-Einstein Dark Matter

Understand

The large dark cores of common dwarf galaxies are unexplained by the standard heavy particle interpretation of dark matter.

• This puzzle is exacerbated by the discovery of a very large but barely visible, dark matter dominated galaxy Antlia II orbiting the Milky Way, uncovered by tracking star motions with the {\t Gaia} satellite.
• Although Antlia II has a low mass, its visible radius is more than double any known dwarf galaxy, with an unprecedentedly low density core.
• We show that Antlia II favors dark matter as a Bose-Einstein condensate, for which the ground state is a stable soliton with a core radius given by the de Broglie wavelength.