Topic summary
Dwarf Galaxies
Extracted from the Wikipedia article Dwarf galaxy.
Local dwarf galaxies
There are many dwarf galaxies in the Local Group; these small galaxies frequently orbit larger galaxies, such as the Milky Way, the Andromeda Galaxy and the Triangulum Galaxy. A 2007 paper has suggested that many dwarf galaxies were created by galactic tides during the early evolutions of the Milky Way and Andromeda. Tidal dwarf galaxies are produced when galaxies collide and their gravitational masses interact. Streams of galactic material are pulled away from the parent galaxies and the halos of dark matter that surround them. A 2018 study suggests that some local dwarf galaxies formed extremely early, during the Dark Ages within the first billion years after the Big Bang. Additionally, recent studies also show nearby star-forming dwarf galaxies have systems that may have formed most of their stellar mass within the last billion years, indicated by blue colours, high star-formation rates, and low metallicities.