These objects, which contain the Tarantula nebula, were the source of the Cepheid variables used by Henrietta Leavitt in her period-luminosity studies.
A population of high-mass x-ray binaries exist in a stellar "bridge" named for these astronomical objects, which also include the stars R85 and S-Doradus. In one of these objects, a blue supergiant named Sanduleak became the SN-1987A supernova. Both ram-pressure stripping and tidal forces have been suggested as causes for the formation of a high-velocity (*) "stream" of gas extending from these objects to the Milky Way. These objects, which contain the Tarantula nebula, were the source of the Cepheid variables used by Henrietta Leavitt in her period-luminosity studies. These objects both orbit the Milky Way and are only visible on Earth from the Southern Hemisphere. For 10 points, name this pair of dwarf galaxies named for a Portuguese explorer. 
A population of high-mass x-ray binaries exist in a stellar "bridge" named for these astronomical objects, which also include the stars R85 and S-Doradus.
Magellanic clouds [prompt on "(dwarf) galaxies"; accept Large and Small Magellanic clouds or Magellanic Bridge/Stream] 