Dwarf galaxies

(A) A dark matter map in our neighbourhood of the universe. The two large densities are dark matter halos of the Milky Way and Andromeda galaxy; (B) Zoomed-in on the dark matter map, showing a small dark matter clump ~700 million years after the Big Bang; (C-1 and C-2) stars and gas in the simulated ultra-faint dwarf galaxy, formed in the centre of the small dark matter halo in panel B. The two panels show two different radiation levels shortly after the Big Bang. It reveals how the ultra-faint dwarf galaxy changes its properties depending on which radiation is used. The scale on each image is in units of light years.