The Interior Field of a Magnetized Einstein-Maxwell Object
  Using the Harmonic map ansatz, we reduce the axisymmetric, static Einstein-Maxwell equations coupled with a magnetized perfect fluid to a set of Poisson-like equations. We were able to integrate the Poisson equations in terms of an arbitrary function $M=M(\rho,\zeta)$ and some integration constants. The thermodynamic equation restricts the solutions to only some state equations, but in some cases when the solution exists, the interior solution can be matched with the corresponding exterior one. 
Tonatiuh Matos (cinvestav-Mexico)