  We analyze a minimal model for a rigid spherical microswimmer and explore the
consequences of its extended surface on the interplay between its
self-propulsion and flow properties. The model is the first order
representation of microswimmers, such as bacteria and algae, with rigid bodies
and flexible propelling appendages. The flow field of such a microswimmer at
finite distances significantly differs from that of a point-force (Stokeslet)
dipole. For a suspension of microswimmers, we derive the grand mobility matrix
that connects the motion of an individual swimmer to the active and passive
forces and torques acting on all the swimmers. Our investigation of the
mobility tensors reveals that hydrodynamic interactions among rigid-bodied
microswimmers differ considerably from those among the corresponding
point-force dipoles. Our results are relevant for the study of collective
behavior of hydrodynamically interacting microswimmers by means of Stokesian
dynamics simulations at moderate concentrations.
