Halosat — A Cubesat That Studied The Hot Galactic Halo

HaloSat was the first CubeSat competitively funded by NASA's Astrophysics Division and performed a two-year, all-sky survey in the soft X-ray band (0.4-2 keV). HaloSat's primary goal was to measure line emission from highly ionized oxygen within the halo or circumgalactic medium of the Milky Way. HaloSat data have also been used to study extended soft X-ray sources such as the North Polar Spur and the Cygnus superbubble and to search for 3.5 keV line emission from a putative sterile neutrino. The full HaloSat data set has been archived at NASA's HEASARC and is publicly available for analysis by the astronomical community. We describe some key results from HaloSat.