Besides the hot gas in the CGM, what other orbiting structures contribute to accounting for some of the Milky Way's missing mass census?

Answer

Recycled dwarf galaxies

Smaller, orbiting companion systems, specifically dwarf galaxies that have undergone multiple cycles of star birth and death, also contain processed matter that contributes to the overall accounting of the galaxy's mass.

Besides the hot gas in the CGM, what other orbiting structures contribute to accounting for some of the Milky Way's missing mass census?
galaxyAstronomerdark mattermassMilky Way