Presentation #110.18 in the session LEM.
We present an overview of the Line Emission Mapper (LEM) mission concept that is under development in anticipation of NASA’s Astrophysics Probe Explorer (APEX) Announcement of Opportunity. LEM combines a wide-field, soft X-ray optic based on the Si-meta shell technology with a transition edge sensor (TES) microcalorimeter array at the focal plane (30’x30’ FOV, 0.2-2.0 keV band pass, 1500 cm2 at 0.5 keV). The TES absorber thickness is optimized for spectral resolution in the LEM band and provides 1 eV resolution in the central 8’x8’ region with the large FOV filled out using multi-absorber pixels (hydras) with 2 eV resolution. Our mission is optimized to address key questions outlined in the Astro2020 Decadal under the broad heading of Cosmic Ecosystems. The combination of a wide-field optic and a microcalorimeter focal plane array with 1-2 eV spectral resolution offers unprecedented sensitivity to extended low-surface brightness X-ray emission. Our primary science will be to map in emission the temperature, entropy, and elemental abundances from diffuse gas in the extended X-ray haloes 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 offer paradigm-changing investigations of feedback, gas dynamics, and metal enrichment over six orders of magnitude in spatial scales from pcs to Mpcs. In addition, LEM will provide the entire international X-ray astrophysics community with a powerful new tool for transformative observations in the areas of active galaxies, stellar astrophysics, planetary sciences, time domain and multi-messenger astrophysics. In this poster, we will present an overview of the LEM science instrumentation and mission capabilities.