Abstract

The prominent stellar bodies of galaxies are surrounded by extended, faint envelopes of stars, often called stellar halos or intra-cluster light. The Milky Way and Andromeda have played a special role in guiding our understanding of the structure and origin of stellar halos, and will continue to do so in the age of Gaia and spectral surveys. Furthermore, new windows are opening up on the low surface brightness components of extragalactic objects, both via resolved stellar-population studies as well as integrated-light imaging to ever deeper surface brightness limits. In parallel, theoretical models (both ab initio hydrodynamical simulations as well as stellar-painting and controlled N-body numerical experiments) provide a foundation for interpreting these observations. They provide insight on the connection between stellar halos and intra-cluster stars to the hierarchical growth of structure in the LCDM cosmology. This meeting aims to put together a comprehensive overview of our understanding or ignorance about galaxy stellar outskirts and stellar halos across all accessible galaxy mass scales, redshifts, and methodologies. By stellar halos we mean both structured and seemingly smooth distributions of stars beyond the central bright bodies of galaxies, and hence including streams, shells, satellite galaxies and intra-cluster light. The advent of new data from ground-based and space telescopes over the next decade (e.g., Gaia, LSST, JWST, Euclid, GMT, TMT, E-ELT, WFIRST), with their resolved wide-field surveys, will provide the tools to put into effect the goals of "near-field cosmology”. Both observational and theoretical methods need to be refined and scaled up in order to process and extract the information content of the thousands of observed stellar halos that will become available in the near future.