Type D perfect-fluid spacetimes with a non-null electromagnetic field. i

The author investigates completely aligned, Petrov type D solutions of the Einstein-Maxwell field equations, which have a perfect fluid and an (non-null) electromagnetic field as source, subject to the additional assumption that the magnetic part of the Weyl tensor relative to the fluid 4-velocity, is zero. The author indicates how all such solutions may be naturally classified into two classes, depending on whether or not the invariants associated with the Weyl, trace-free Ricci and Maxwell tensors are independent. A detailed study, centred about conditions for zero vorticity in the fluid flow, is carried out on the functionally independent class. Further, we present new solutions, which belong to this class, some of which may be of interest in the study of gravitational collapse as well as possibly providing suitable cosmological models for early epochs of our Universe.