The Line Emission Mapper (LEM) Probe mission concept

The Line Emission Mapper (LEM) is a Probe mission concept developed in response to NASA’s APEX AO. LEM consists of one science instrument composed of a large area, wide-field X-ray optic and a microcalorimeter X-ray imaging spectrometer. LEM is optimized to observe low-surface brightness diffuse X-ray emission over a 30’x30’ field of view with 1.3-2.5 eV spectral resolution in the 0.2-2.0 keV band. Our primary science will be to map in emission the thermal, kinetic, and elemental properties of the diffuse gas in galaxies, the outskirts of galaxy clusters and the filamentary structures between these clusters, and in the Milky Way star formation regions and Galactic halo, and Galactic and Local Group supernova remnants. LEM will spend ~11% of its five-year prime science mission performing an All-Sky Survey – the first All-Sky X-ray survey at high spectral resolution. The remainder of the time will be divided between the directed science (30%) and competed General Observer science (70%). In this presentation, we will give a mission overview, the directed science that drives the mission design, and the broad scope that these capabilities offer the astrophysics community.