Surveying the Agents of a Galaxy's Evolution

Three key science goals determined the coverage and depth of the survey. The detection of diffuse ISM with column densities >1.2×1021 H cm-2 permits detailed studies of dust processes in the ISM.

SAGE's point-source sensitivity enables a complete census of newly formed stars with masses >3 Msolar that will determine the current star formation rate in the LMC. SAGE's detection of evolved stars with mass-loss rates >1×10-8 Msolar yr-1 will quantify the rate at which evolved stars inject mass into the ISM of the LMC. The observing strategy includes two epochs in 2005, separated by 3 months, that both mitigate instrumental artifacts and constrain source variability.