  Optomagnonic systems, where light couples coherently to collective
excitations in magnetically ordered solids, are currently of high interest due
to their potential for quantum information processing platforms at the
nanoscale. Efforts so far, both at the experimental and theoretical level, have
focused on systems with a homogeneous magnetic background. A unique feature in
optomagnonics is however the possibility of coupling light to spin excitations
on top of magnetic textures. We propose a cavity-optomagnonic system with a non
homogeneous magnetic ground state, namely a vortex in a magnetic microdisk. In
particular we study the coupling between optical whispering gallery modes to
magnon modes localized at the vortex. We show that the optomagnonic coupling
has a rich spatial structure and that it can be tuned by an externally applied
magnetic field. Our results predict cooperativities at maximum photon density
of the order of $\mathcal{C}\approx10^{-2}$ by proper engineering of these
structures.
