Critical Behaviour and Universality in Gravitational Collapse of a Charged Scalar Field

We summarize results from a study of spherically symmetric collapse of a charged (complex) massless scalar-field [1]. We present an analytic argument which conjecture the generalization of the mass-scaling relation and echoing phenomena, originally discovered by Choptuik, for the charged case. Furthermore, we study the behaviour of the self-similar critical solution under external perturbations – addition of a cosmological constant Λ and a chargeconjugation e. Finally, we study the scaling-relation of the black-hole charge. Using an analytic argument we conjecture that black-holes of infinitesimal mass are neutral or obey the relation QBH ≪ MBH . We verify our predictions with numerical results.