Planck Collaboration, P. A. R. Ade, N. Aghanim, M. Arnaud, M. Ashdown, J. Aumont, C. Baccigalupi, A. Balbi, A. J. Banday, R. B. Barreiro, J. G. Bartlett, E. Battaner, K. Benabed, A. Benoît, J. -P. Bernard, I. Bikmaev, H. Böhringer, A. Bonaldi, S. Borgani, J. Borrill, F. R. Bouchet, M. L. Brown, C. Burigana, R. C. Butler, P. Cabella, P. Carvalho, A. Catalano, L. Cayón, A. Chamballu, R. -R. Chary, L. -Y Chiang, G. Chon, P. R. Christensen, D. L. Clements, S. Colafrancesco, S. Colombi, B. P. Crill, F. Cuttaia, A. Da Silva, H. Dahle, R. J. Davis, P. de Bernardis, G. de Gasperis, G. de Zotti, J. Delabrouille, J. Démoclès, F. -X. Désert, J. M. Diego, K. Dolag, H. Dole, S. Donzelli, O. Doré, M. Douspis, X. Dupac, T. A. Enßlin, H. K. Eriksen, F. Finelli, I. Flores-Cacho, M. Frailis, E. Franceschi, M. Frommert, S. Galeotta, K. Ganga, R. T. Génova-Santos, Y. Giraud-Héraud, J. González-Nuevo, R. González-Riestra, K. M. Górski, A. Gregorio, F. K. Hansen, D. Harrison, S. Henrot-Versillé, C. Hernández-Monteagudo, D. Herranz, S. R. Hildebrandt, E. Hivon, M. Hobson, W. A. Holmes, A. Hornstrup, W. Hovest, K. M. Huffenberger, G. Hurier, A. H. Jaffe, T. Jagemann, W. C. Jones, M. Juvela, R. Kneissl, J. Knoche, L. Knox, M. Kunz, H. Kurki-Suonio, G. Lagache, J. -M. Lamarre, A. Lasenby, C. R. Lawrence, M. Le Jeune, S. Leach, R. Leonardi, A. Liddle, P. B. Lilje, M. Linden-Vornle, M. López-Caniego, G. Luzzi, J. F. Macías-Pérez, D. Maino, R. Mann, F. Marleau, D. J. Marshall, E. Martínez-González, S. Masi, M. Massardi, S. Matarrese, P. Mazzotta, S. Mei, A. Melchiorri, J. -B. Melin, L. Mendes, A. Mennella, S. Mitra, M. -A. Miville-Deschênes, A. Moneti, G. Morgante, D. Mortlock, D. Munshi, P. Naselsky, F. Nati, H. U. Norgaard-Nielsen, F. Noviello, S. Osborne, F. Pajot, D. Paoletti, O. Perdereau, F. Perrotta, F. Piacentini, M. Piat, E. Pierpaoli, R. Piffaretti, S. Plaszczynski, P. Platania, E. Pointecouteau, G. Polenta, L. Popa, T. Poutanen, G. W. Pratt, S. Prunet, J. -L. Puget, M. Reinecke, M. Remazeilles, C. Renault, S. Ricciardi, G. Rocha, C. Rosset, M. Rossetti, J. A. Rubiño-Martín, B. Rusholme, M. Sandri, G. Savini, D. Scott, G. F. Smoot, A. Stanford, F. Stivoli, R. Sudiwala, R. Sunyaev, D. Sutton, J. -F. Sygnet, J. A. Tauber, L. Terenzi, L. Toffolatti, M. Tomasi, M. Tristram, L. Valenziano, B. Van Tent, P. Vielva, F. Villa, N. Vittorio, L. A. Wade, B. D. Wandelt, N. Welikala, J. Weller, S. D. M. White, D. Yvon, A. Zacchei, A. Zonca
We present the final results from the XMM-Newton validation follow-up of new Planck cluster candidates. We observed 15 new candidates, detected with signal-to-noise ratios between 4.0 and 6.1 in the 15.5-month nominal Planck survey. The candidates were selected using ancillary data flags derived from the ROSAT All Sky Survey (RASS) and Digitized Sky Survey all-sky maps, with the aim of pushing into the low SZ flux, high- z regime and testing RASS flags as indicators of candidate reliability. 14 new clusters were detected by XMM-Newton, 10 single clusters and 2 double systems. Redshifts from X-ray spectroscopy lie in the range 0.2 to 0.9, with six clusters at z>0.5. Estimated M500 ranges from 2.5 X 10^14 to 8 X 10^14 Msun. We discuss our results in the context of the full XMM validation programme, in which 51 new clusters have been detected. This includes 4 double and 2 triple systems, some of which are chance projections on the sky of clusters at different redshifts. Association with a source from the RASS-Bright Source Catalogue is a robust indicator of candidate reliability, whereas association with a source from the RASS-Faint Source Catalogue does not guarantee that the SZ candidate is a bona fide cluster. Most Planck clusters appear in RASS maps, with a significance greater than 2 sigma being a good indication of a real cluster. The full sample indicates a Planck sensitivity threshold of Y500 ~ 4 X 10^-4 arcmin^2, with indication for Malmquist bias in the YX-Y500 relation below this level. The corresponding mass threshold depends on redshift. Systems with M500 > 5 X 10^14 Msun at z>0.5 are easily detectable with Planck. The newly-detected clusters follow the YX-Y500 relation derived from X-ray selected samples, with no indication of evolution. Compared to X-ray selected clusters, the new SZ clusters are underluminous on average for their mass, at all redshifts.
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http://arxiv.org/abs/1205.3376
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