  A fundamental prediction of the Lambda Cold Dark Matter (LCDM) cosmology is
the centrally divergent cuspy density profile of dark matter haloes. Density
cusps render CDM haloes resilient to tides, and protect dwarf galaxies embedded
in them from full tidal disruption. The hierarchical assembly history of the
Milky Way may therefore give rise to a population of micro galaxies; i.e.,
heavily stripped remnants of early accreted satellites, which may reach
arbitrarily low luminosity. Assuming that the progenitor systems are dark
matter dominated, we use an empirical formalism for tidal stripping to predict
the evolution of the luminosity, size, and velocity dispersion of such
remnants, tracing their tidal evolution across multiple orders of magnitude in
mass and size. The evolutionary tracks depend sensitively on the progenitor
distribution of stellar binding energies. We explore three cases that likely
bracket most realistic models of dwarf galaxies: one where the energy
distribution of the most tightly bound stars follows that of the dark matter,
and two where stars are defined by either an exponential density or surface
brightness profile. The tidal evolution in the size-velocity dispersion plane
is quite similar for these three models, although their remnants may differ
widely in luminosity. Micro galaxies are therefore best distinguished from
globular clusters by the presence of dark matter; either directly, by measuring
their velocity dispersion, or indirectly, by examining their tidal resilience.
Our work highlights the need for further theoretical and observational
constraints on the stellar energy distribution in dwarf galaxies.
