[1] Ctr Fermi Museo Stor Fis, I-00184 Rome, Italy
[2] Ctr Studi & Ric Enrico, I-00184 Rome, Italy
[3] INFN, Sez Torino, Via P Giuria 1, I-10125 Turin, Italy
[4] Inst Hautes Etud Sci, F-91440 Bures Sur Yvette, France
[5] Friedrich Schiller Univ Jena, Inst Theoret Phys, D-07743 Jena, Germany
[6] Ist Nazl Fis Nucl, Sez Milano Bicocca, Grp Collegato Parma, I-43124 Parma, Italy
[7] Univ Parma, Dept Math Phys & Comp Sci, I-43124 Parma, Italy
[8] Univ Pisa, Dipartimento Fis Enrico Fermi, I-56127 Pisa, Italy
[9] INFN, Sez Pisa, I-56127 Pisa, Italy
[10] Univ Torino, Dipartimento Fis, Via P Giuria 1, I-10125 Turin, Italy
[11] Max Planck Inst Dynam & Self Org, D-37077 Gottingen, Germany
[12] Univ Paris 07, CNRS, APC, F-75205 Paris 13, France
[13] Moscow Inst Phys & Technol, Dolgoprudnyi, Moscow Region, Russia
[14] Univ Illes Balears, IAC3 IEEC, Palma De Mallorca 07122, Spain
[15] Univ Milano Bicocca, Dipartimento Fis, Piazza Sci 3, I-20126 Milan, Italy
[16] INFN, Sez Milano Bicocca, Piazza Sci 3, I-20126 Milan, Italy
[17] Princeton Univ, Dept Astrophys Sci, 4 Ivy Lane, Princeton, NJ 08544 USA
[18] Inst Adv Study, 1 Einstein Dr, Princeton, NJ 08540 USA
[19] Univ Cambridge, Ctr Math Sci, DAMTP, Wilberforce Rd, Cambridge CB3 0WA, England
[20] Cardiff Univ, Sch Phys & Astron, Grav Explorat Inst, Cardiff CF24 3AA, S Glam, Wales
[21] Albert Einstein Inst, Max Planck Inst Gravitat Phys, Muhlenberg 1, D-14476 Potsdam, Germany
[22] Univ Valencia, Dept Astron & Astrofs, Doctor Moliner 50, E-46100 Valencia, Spain
[23] Univ Valencia, Astron Observ, C Catedrat Jose Beltran 2, Valencia 46980, Spain
[24] Univ Roma Sapienza, Dipartimento Fis, Piazzale A Moro 5, I-00185 Rome, Italy
[25] Sez INFN Roma1, Piazzale A Moro 5, I-00185 Rome, Italy
[26] Radboud Univ Nijmegen, Dept Astrophys IMAPP, POB 9010, NL-6525 GL Nijmegen, Netherlands