Shearfree and conformally Ricci-flat perfect fluids
It is shown that all relativistic shear-free perfect fluid solutions with a space-time metric conformally related to a vacuum solution are either of Petrov type D, as well as locally rotationally symmetric, or are conformally flat. That is, the author investigates the general case where the gradient of the conformal scalar field makes an arbitrary angle with the fluid velocity.
relativistic shear-free perfect fluid solutions
scientific article; zbMATH DE number 3972532