  This paper introduces SMACC -- Subhalo Mass-loss Analysis using Core
Catalogs. SMACC adds a mass model to substructure merger trees based on halo
"core tracking." Our approach avoids the need for running expensive subhalo
finding algorithms and instead uses subhalo mass-loss modeling to assign masses
to halo cores. We present details of the SMACC methodology and demonstrate its
excellent performance in describing halo substructure and its evolution.
Validation of the approach is carried out using cosmological simulations at
significantly different resolutions. We apply SMACC to the 1.24
trillion-particle Last Journey simulation and construct core catalogs with the
additional mass information. These catalogs can be readily used as input to
semi-analytic models or subhalo abundance matching approaches to determine
approximate galaxy distributions, as well as for in-depth studies of
small-scale structure evolution.
