We present an analysis of Planck satellite data on the Coma Cluster observed via the Sunyaev-Zeldovich effect. Planck is able, for the first time, to detect SZ emission up to r ~ 3 X R_500. We test previously proposed models for the pressure distribution in clusters against the azimuthally averaged data. We find that the Arnaud et al. universal pressure profile does not fit Coma, and that their pressure profile for merging systems provides a good fit of the data only at rR_500 than the mean pressure profile predicted by the simulations. The Planck image shows significant local steepening of the y profile in two regions about half a degree to the west and to the south-east of the cluster centre. These features are consistent with the presence of shock fronts at these radii, and indeed the western feature was previously noticed in the ROSAT PSPC mosaic by Markevitch (2000) as well as in the radio. Using Planck y profiles extracted from corresponding sectors we find pressure jumps of 4.5+2.5-0.1 and 4.9+0.7-0.2 in the west and southeast, respectively. Assuming Rankine-Hugoniot pressure jump conditions, we deduce that the shock waves should propagate with Mach number M_w=1.95+0.45-0.02 and M_se=2.03+0.14-0.04 in the West and Southeast, respectively. Finally, we find that the y and radio-synchrotron signals are quasi-linearly correlated on Mpc scales with small intrinsic scatter. This implies either that the energy density of cosmic-ray electrons is relatively constant throughout the cluster, or that the magnetic fields fall off much more slowly with radius than previously thought.

Planck intermediate results. X. Physics of the hot gas in the Coma cluster / P.A.R. Ade, N. Aghanim, M. Arnaud, M. Ashdown, F. Atrio Barandela, J. Aumont, C. Baccigalupi, A. Balbi, A.J. Banday, R.B. Barreiro, J.G. Bartlett, E. Battaner, K. Benabed, A. Benoît, J.P. Bernard, M. Bersanelli, A. Bonaldi, J.R. Bond, J. Borrill, F.R. Bouchet, H. Bourdin, M.L. Brown, S.D. Brown, C. Burigana, P. Cabella, J.F. Cardoso, P. Carvalho, A. Catalano, L. Cayón, L.Y. Chiang, G. Chon, P.R. Christensen, E. Churazov, D.L. Clements, S. Colafrancesco, L.P.L. Colombo, A. Coulais, B.P. Crill, F. Cuttaia, A. Da Silva, H. Dahle, L. Danese, R.J. Davis, P. de Bernardis, G. de Gasperis, A. de Rosa, G. de Zotti, J. Delabrouille, F.X. Désert, C. Dickinson, J.M. Diego, K. Dolag, H. Dole, S. Donzelli, O. Doré, U. Dörl, M. Douspis, X. Dupac, T.A. Enßlin, H.K. Eriksen, F. Finelli, I. Flores Cacho, O. Forni, M. Frailis, E. Franceschi, M. Frommert, S. Galeotta, K. Ganga, R.T. Génova Santos, M. Giard, M. Gilfanov, J. González Nuevo, K.M. Górski, A. Gregorio, A. Gruppuso, F.K. Hansen, D. Harrison, S. Henrot Versillé, C. Hernández Monteagudo, S.R. Hildebrandt, E. Hivon, M. Hobson, W.A. Holmes, A. Hornstrup, W. Hovest, K.M. Huffenberger, G. Hurier, T.R. Jaffe, T. Jagemann, W.C. Jones, M. Juvela, E. Keihänen, R. Kneissl, J. Knoche, L. Knox, M. Kunz, H. Kurki Suonio, G. Lagache, A. Lähteenmäki, A. Lasenby, C.R. Lawrence, M. Le Jeune, R. Leonardi, P.B. Lilje, M. Linden Vørnle, M. López Caniego, P.M. Lubin, J.F. Macías Pérez, B. Maffei, D. Maino, N. Mandolesi, M. Maris, F. Marleau, E. Martínez González, S. Masi, M. Massardi, S. Matarrese, F. Matthai, P. Mazzotta, S. Mei, A. Melchiorri, J.B. Melin, L. Mendes, A. Mennella, S. Mitra, M.A. Miville Deschênes, A. Moneti, L. Montier, G. Morgante, D. Munshi, J.A. Murphy, P. Naselsky, P. Natoli, H.U. Nørgaard Nielsen, F. Noviello, S. Osborne, F. Pajot, D. Paoletti, O. Perdereau, F. Perrotta, F. Piacentini, M. Piat, E. Pierpaoli, R. Piffaretti, S. Plaszczynski, E. Pointecouteau, G. Polenta, N. Ponthieu, L. Popa, T. Poutanen, G.W. Pratt, S. Prunet, J.L. Puget, J.P. Rachen, R. Rebolo, M. Reinecke, M. Remazeilles, C. Renault, S. Ricciardi, T. Riller, G. Rocha, M. Roman, C. Rosset, M. Rossetti, J.A. Rubiño Martín, L. Rudnick, B. Rusholme, M. Sandri, G. Savini, B.M. Schaefer, D. Scott, G.F. Smoot, F. Stivoli, R. Sudiwala, R. Sunyaev, D. Sutton, A.S. Suur Uski, J.F. Sygnet, J.A. Tauber, L. Terenzi, L. Toffolatti, M. Tomasi, M. Tristram, J. Tuovinen, M. Türler, G. Umana, L. Valenziano, B. Van Tent, J. Varis, P. Vielva, F. Villa, N. Vittorio, L.A. Wade, B.D. Wandelt, N. Welikala, S.D.M. White, D. Yvon, A. Zacchei, S. Zaroubi, A. Zonca. - In: ASTRONOMY & ASTROPHYSICS. - ISSN 0004-6361. - 554(2013 Jun), pp. A140.1-A140.19. [10.1051/0004-6361/201220247]

Planck intermediate results. X. Physics of the hot gas in the Coma cluster

M. Bersanelli;L.P.L. Colombo;S. Donzelli;D. Maino;A. Mennella;M. Rossetti;M. Tomasi;A. Zonca
2013-06

Abstract

We present an analysis of Planck satellite data on the Coma Cluster observed via the Sunyaev-Zeldovich effect. Planck is able, for the first time, to detect SZ emission up to r ~ 3 X R_500. We test previously proposed models for the pressure distribution in clusters against the azimuthally averaged data. We find that the Arnaud et al. universal pressure profile does not fit Coma, and that their pressure profile for merging systems provides a good fit of the data only at rR_500 than the mean pressure profile predicted by the simulations. The Planck image shows significant local steepening of the y profile in two regions about half a degree to the west and to the south-east of the cluster centre. These features are consistent with the presence of shock fronts at these radii, and indeed the western feature was previously noticed in the ROSAT PSPC mosaic by Markevitch (2000) as well as in the radio. Using Planck y profiles extracted from corresponding sectors we find pressure jumps of 4.5+2.5-0.1 and 4.9+0.7-0.2 in the west and southeast, respectively. Assuming Rankine-Hugoniot pressure jump conditions, we deduce that the shock waves should propagate with Mach number M_w=1.95+0.45-0.02 and M_se=2.03+0.14-0.04 in the West and Southeast, respectively. Finally, we find that the y and radio-synchrotron signals are quasi-linearly correlated on Mpc scales with small intrinsic scatter. This implies either that the energy density of cosmic-ray electrons is relatively constant throughout the cluster, or that the magnetic fields fall off much more slowly with radius than previously thought.
Cosmic background radiation; Cosmology: observations; Galaxies: clusters: general; Galaxies: clusters: individual: Coma cluster; Galaxies: clusters: intracluster medium; X-rays: galaxies: clusters
Settore FIS/05 - Astronomia e Astrofisica
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/230304
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