Beyond the Edge of the Milky Way: Giant Pulsating Stars Revealed an Enormous Halo of Dark Matter

Galaxy NGC 474


One early result of the 2nd release of the still ongoing Dark Energy Survey is the previously untold story revealed by old, giant RR Lyrae (RRL) pulsating stars with a mass of around half the sun’s, which tell scientists about the region of space beyond the edge of our Milky Way. These large-amplitude stars serve as tracers and distance indicators of old stellar populations in the Milky Way and neighboring galaxies. They are also essential laboratories for testing evolutionary and pulsation models.