Electromagnetic mass model admitting conformal motion
  We study charged fluid spheres under the 4-dimensional Einstein-Maxwell space-time. The solutions thus obtained admitting conformal motion. We also investigate whether the solutions set provide electromagnetic mass models such that the physical parameters including the gravitational mass arise from the electromagnetic field alone. In this connection three cases are studied here in detail with the propositions: (1) $p = - \rho$, (2) $\sigma e^{\lambda/2} = \sigma_0$ and (3) $8 \pi p - E^2 = p_0$ where $\rho$, $p$, $\sigma$ are respectively the usual matter density, fluid pressure and charge density of the spherical distribution. Based on these assumptions several features are explored which seems physically very interesting. 
Saibal Ray, A A Usmani, F Rahaman, M Kalam and K Chakraborty