Mapping the Sky at MeV Energies with the Lunar Occultation Explorer

The Lunar Occultation Explorer (LOX) is an Astrophysics Explorer mission recently proposed to NASA, with the goal of using the Lunar Occultation Technique (LOT) to make sensitive studies of MeV gamma-ray emission form Type Ia Supernovae. Here we present a study of the potential for LOX to create maps of the MeV sky with unprecedented angular resolution using the same technique, taking advantage of the sharp lunar limb and stable background environment in lunar orbit. Using the proposed LOX orbit, the lunar disk is projected onto a simulated MeV gamma-ray sky that includes diffuse Galactic emission predicted by the GALPROP package and point sources extrapolated from the Fermi catalog. The expected count rate differences over the LOX spectrum accumulation time are assigned to locations on the sky associated with the rising and setting lunar limbs, and the averages of these differences over time create a sky map from 0.5–10 MeV. We show that an angular resolution of 0.5° or better can be achieved, allowing sensitive studies of slowly-varying MeV gamma ray sources.