s4g.caltech.edu

Motivation: Galaxies are the basic building blocks of the Universe, and understanding their formation and evolution is crucial to many areas of current astrophysical research. Nearby galaxies, being the 'fossil record' of the evolution of galaxies, provide a wealth of detail to test extensively the current models of galaxy formation and evolution. A galaxy's structure is linked to both its mass and evolutionary history. Probing galactic structure requires understanding the distribution of stars among galaxies of all types and luminosities across the full range of environments. We propose a complete volume-limited (d < 40 Mpc) survey of nearby spiral, elliptical and dwarf galaxies at 3.6 and 4.5μm in the Spitzer Warm Mission to address fundamental questions of galactic structure that are united by the common need for deep, uniform, unbiased maps of the stellar mass in galaxies.