Presentation #149.04 in the session “Dark Matter”.
An X-ray emission line near 3.5 keV observed in dark matter dominated objects (galaxy clusters, the Milky Way galaxy) has been interpreted as a possible secondary product of a decaying dark matter particle, though observations of the line have been controversial. One possible dark matter particle candidate that could explain the 3.5 keV line is a sterile neutrino with a mass of ~7 keV. If this interpretation of the line is correct, there should exist a signal from the Milky Way that is correlated to models of the Milky Way galaxy’s dark matter distribution. HaloSat is an all-sky survey that, since October 2018, has been observing in the soft X-ray band from 0.4 - 7 keV. With its large field of view (~100 deg2) and significant coverage of the X-ray sky, HaloSat provides an opportunity to search for the 3.5 keV line originating from the Milky Way. Observations from HaloSat may provide additional information to previous studies of the line with XMM-Newton and Chandra. We report on the expected HaloSat sensitivity to the 3.5 keV line and current work on modeling the astrophysical and instrumental background components to HaloSat data in the search for the 3.5 keV line.