Superkicks in ultrarelativistic encounters of spinning black holes

Ulrich Sperhake, Emanuele Berti, Vitor Cardoso, Frans Pretorius, and Nicolas Yunes Institut de Ciències de l’Espai (CSIC-IEEC), Facultat de Ciències, Campus UAB, E-08193 Bellaterra, Spain California Institute of Technology, Pasadena, California 91125, USA Department of Physics and Astronomy, The University of Mississippi, University, Mississippi 38677, USA CENTRA, Departamento de Fı́sica, Instituto Superior Técnico, Universidade Técnica de Lisboa-UTL, Av. Rovisco Pais 1, 1049 Lisboa, Portugal Department of Physics, Princeton University, Princeton, New Jersey 08544, USA Department of Physics and MIT Kavli Institute, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138, USA (Received 22 November 2010; published 28 January 2011)