February
2013
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2013A&A...550A.134P
Authors
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Planck Collaboration
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Ade, P. A. R.
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Aghanim, N.
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Arnaud, M.
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Ashdown, M.
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Atrio-Barandela, F.
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Aumont, J.
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Baccigalupi, C.
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Balbi, A.
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Banday, A. J.
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Barreiro, R. B.
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Battaner, J. G. Bartlett E.
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Benabed, K.
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Benoît, A.
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Bernard, J. -P.
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Bersanelli, M.
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Bhatia, R.
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Bikmaev, I.
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Böhringer, H.
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Bonaldi, A.
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Bond, J. R.
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Borrill, J.
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Bouchet, F. R.
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Bourdin, H.
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Burenin, R.
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Burigana, C.
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Cabella, P.
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Cardoso, J. -F.
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Castex, G.
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Catalano, A.
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Cayón, L.
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Chamballu, A.
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Chary, R. -R.
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Chiang, L. -Y.
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Chon, G.
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Christensen, P. R.
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Clements, D. L.
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Colafrancesco, S.
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Colombo, L. P. L.
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Comis, B.
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Coulais, A.
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Crill, B. P.
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Cuttaia, F.
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Danese, L.
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Davis, R. J.
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de Bernardis, P.
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de Gasperis, G.
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de Zotti, G.
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Delabrouille, J.
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Démoclès, J.
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Désert, F. -X.
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Diego, J. M.
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Dolag, K.
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Dole, H.
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Donzelli, S.
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Doré, O.
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Dörl, U.
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Douspis, M.
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Dupac, X.
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Efstathiou, G.
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Enßlin, T. A.
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Eriksen, H. K.
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Finelli, F.
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Flores-Cacho, I.
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Forni, O.
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Frailis, M.
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Franceschi, E.
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Frommert, M.
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Ganga, K.
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Génova-Santos, T.
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Giard, M.
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Gilfanov, M.
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Giraud-Héraud, Y.
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González-Nuevo, J.
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Górski, K. M.
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Gregorio, A.
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Gruppuso, A.
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Hansen, F. K.
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Harrison, D.
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Hempel, A.
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Henrot-Versillé, S.
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Hernández-Monteagudo, C.
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Herranz, D.
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Hildebrandt, S. R.
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Hivon, E.
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Hobson, M.
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Holmes, W. A.
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Hovest, W.
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Hurier, G.
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Jaffe, T. R.
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Jaffe, A. H.
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Jagemann, T.
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Jones, W. C.
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Juvela, M.
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Khamitov, I.
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Kisner, T. S.
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Kneissl, R.
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Knoche, J.
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Knox, L.
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Kunz, M.
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Kurki-Suonio, H.
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Lagache, G.
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Lamarre, J. -M.
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Lasenby, A.
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Lawrence, C. R.
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Le Jeune, M.
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Leonardi, R.
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Lilje, P. B.
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Linden-Vørnle, M.
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López-Caniego, M.
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Lubin, P. M.
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Luzzi, G.
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Macías-Pérez, J. F.
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Maffei, B.
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Maino, D.
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Mandolesi, N.
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Maris, M.
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Marleau, F.
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Marshall, D. J.
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Martínez-González, E.
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Masi, S.
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Massardi, M.
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Matarrese, S.
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Matthai, F.
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Mazzotta, P.
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Mei, S.
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Melchiorri, A.
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Melin, J. -B.
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Mendes, L.
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Mennella, A.
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Mitra, S.
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Miville-Deschènes, M. -A.
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Moneti, A.
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Montier, L.
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Morgante, G.
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Munshi, D.
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Murphy, J. A.
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Naselsky, P.
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Nati, F.
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Natoli, P.
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Nørgaard-Nielsen, H. U.
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Noviello, F.
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Novikov, D.
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Novikov, I.
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Osborne, S.
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Pajot, F.
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Paoletti, D.
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Pasian, F.
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Patanchon, G.
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Perdereau, O.
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Perotto, L.
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Perrotta, F.
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Piacentini, F.
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Piat, M.
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Pierpaoli, E.
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Piffaretti, R.
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Plaszczynski, S.
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Pointecouteau, E.
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Polenta, G.
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Ponthieu, N.
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Popa, L.
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Poutanen, T.
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Pratt, G. W.
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Prunet, S.
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Puget, J. -L.
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Rachen, J. P.
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Rebolo, R.
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Reinecke, M.
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Remazeilles, M.
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Renault, C.
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Ricciardi, S.
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Riller, T.
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Ristorcelli, I.
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Rocha, G.
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Roman, M.
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Rosset, C.
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Rossetti, M.
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Rubiño-Martín, J. A.
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Rusholme, B.
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Sandri, M.
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Savini, G.
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Schaefer, B. M.
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Scott, D.
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Smoot, G. F.
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Starck, J. -L.
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Sudiwala, R.
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Sunyaev, R.
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Sutton, D.
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Suur-Uski, A. -S.
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Sygnet, J. -F.
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Tauber, J. A.
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Terenzi, L.
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Toffolatti, L.
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Tomasi, M.
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Tristram, M.
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Tucci, M.
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Valenziano, L.
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Van Tent, B.
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Vielva, P.
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Villa, F.
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Vittorio, N.
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Wade, L. A.
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Wandelt, B. D.
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Welikala, N.
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White, S. D. M.
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Yvon, D.
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Zacchei, A.
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Zonca, A.
Abstract
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Context. About half of the baryons of the Universe are expected to be in the form of filaments of hot and low-density intergalactic medium. Most of these baryons remain undetected even by the most advanced X-ray observatories, which are limited in sensitivity to the diffuse low-density medium.
Aims: The Planck satellite has provided hundreds of detections of the hot gas in clusters of galaxies via the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for studying extended low-density media through the tSZ effect. In this paper we use the Planck data to search for signatures of a fraction of these missing baryons between pairs of galaxy clusters.
Methods: Cluster pairs are good candidates for searching for the hotter and denser phase of the intergalactic medium (which is more easily observed through the SZ effect). Using an X-ray catalogue of clusters and the Planck data, we selected physical pairs of clusters as candidates. Using the Planck data, we constructed a local map of the tSZ effect centred on each pair of galaxy clusters. ROSAT data were used to construct X-ray maps of these pairs. After modelling and subtracting the tSZ effect and X-ray emission for each cluster in the pair, we studied the residuals on both the SZ and X-ray maps.
Results: For the merging cluster pair A399-A401 we observe a significant tSZ effect signal in the intercluster region beyond the virial radii of the clusters. A joint X-ray SZ analysis allows us to constrain the temperature and density of this intercluster medium. We obtain a temperature of kT = 7.1 ± 0.9 keV (consistent with previous estimates) and a baryon density of (3.7 ± 0.2) × 10-4 cm-3.
Conclusions: The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.
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