  We find the range of parameters for which the open string physics on probe
Dq-branes in the near-horizon geometry of Dp-branes decouples from gravity, and
is well-approximated by a (q+1)-dimensional supersymmetric Yang-Mills-Higgs
theory on a rigid curved spacetime. We study the vacua of these theories, which
include moduli spaces of instantons, monopoles, and vortices. This intricate
structure is made possible through couplings to the background Ramond-Ramond
flux. The probe brane theories we study provide holographic descriptions of
defects in dual field theories.
