1. Department of Physics, University of Illinois, Urbana-Champaign, Urbana, 61801, USA
2. Loomis Laboratory of Physics, 1110 W Green St Loomis Laboratory, Urbana-Champaign, Urbana, 61801, USA
3. INAF, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova, Italy
4. Center for Computational Relativity and Gravitation, & School of Mathematical Sciences, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, New York 14623, USA
5. Dipartimento di Fisica G. Occhialini, Universit`a di Milano-Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy