CONICET | Buscador de Institutos y Recursos Humanos

In this talk we show some results and ideas concerning the existence and properties of the ExtremeBowen-York initial data. It has been known for a long time that the Bowen-York family of spinningblack hole initial data depends essentially on one, postive, free parameter. But even when the presenceof some extreme limit was suggested by numerical experiments, its very existence and main features havenot been completely established. The extreme limit corresponds to making the mentioned parameterequal to zero, and it represents a singular limit for the constraint equations. We prove that in thislimit a new solution of Einstein constraints is obtained and find an interesting ressemblance with otherfamilies of black hole initial data, like Kerr and Reissner-Nordstrom. In particular, in this limit one ofthe asymptotic ends changes from asymptotically flat, to cylindrical. Moreover, the procedure we use inthe proof can be easily extended to more general situations! , indicating some common scenario amongblack hole families, in this extreme limit. Finally, we also discuss different contexts in which these ideasprove to be useful.