  A growing body of evidence suggests that the central density of cuspy dark
matter subhaloes is conserved in minor mergers. However, empirical models of
subhalo evolution, calibrated from simulations, often assume a drop in the
central density. Since empirical models of subhaloes are used in galaxy-galaxy
lensing studies and dark matter annihilation calculations, we explore the
consequences of assuming different subhalo models. We find that dark matter
annihilation calculations are very sensitive to the assumed subhalo mass
profile, and different models can give more than a magnitude difference in the
J-factor and boost factor in individual haloes. On the other hand, the shear
and convergence profiles used in galaxy-galaxy lensing are sensitive to the
initial profile assumed (e.g., NFW versus Einato) but are otherwise
well-approximated by a simple model in which the original profile is sharply
truncated. We conclude that since the innermost parts of haloes are difficult
to resolve in simulations, it is important to have a theoretical understanding
of how subhaloes evolve to make accurate predictions of the dark matter
annihilation signal.
