A milestone for Milky Way home Measuring dark matter in a tidal stream of stars

This video accompanies the press release Ancient Dwarf Galaxy Reconstructed with MilkyWayhome Volunteer Computer, (links and high resolution image can be found at announcing the publication of The Astrophysical Journal paper Estimate of the Mass and Radial Profile of the OrphanChenab Streamʼs Dwarfgalaxy Progenitor Using MilkyWayhome, by Eric J. Mendelsohn, Heidi Jo Newberg, Siddhartha Shelton, Lawrence M. Widrow, Jeffery M. Thompson, and Carl J. Grillmair, February 17, 2022. Prof. Heidi Jo Newberg explains how the MilkyWayhome volunteer supercomputer was used to determine the shape and dark matter content of the ultrafaint dwarf galaxy that fell into the Milky Way three billion years ago and was ripped apart to form the OrphanChenab Stream (OCS). The measured dark matter mass is ten times less than that of dwarf galaxies observed today. This could mean that ultrafaint dwarf galaxy masses are overestimated, or that dwarf galaxies that were ripped apart billions of