Planck intermediate results. X. Physics of the hot gas in the Coma cluster
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 r<R_500: by r=2XR_500 it underestimates the observed y profile by a factor of ~2. This may indicate that at these larger radii either i) the cluster SZ emission is contaminated by unresolved SZ sources along the line of sight or ii) the pressure profile of Coma is higher at r>R_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 as well as in the radio. Using Planck y profiles extracted from corresponding sectors we find pressure jumps of 4.5+0.4-0.2 and 5.0+1.3-0.1 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=2.03+0.09-0.04 and M_se=2.05+0.25-0.02 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.
Keywords
Cite
@article{arxiv.1208.3611,
title = {Planck intermediate results. X. Physics of the hot gas in the Coma cluster},
author = {Planck Collaboration and P. A. R. Ade and N. Aghanim and M. Arnaud and M. Ashdown and F. Atrio-Barandela and J. Aumont and C. Baccigalupi and A. Balbi and A. J. Banday and R. B. Barreiro and J. G. Bartlett and E. Battaner and K. Benabed and A. Benoît and J. -P. Bernard and M. Bersanelli and I. Bikmaev and H. Böhringer and A. Bonaldi and J. R. Bond and J. Borrill and F. R. Bouchet and H. Bourdin and M. L. Brown and S. D. Brown and R. Burenin and C. Burigana and P. Cabella and J. -F. Cardoso and P. Carvalho and A. Catalano and L. Cayón and L. -Y Chiang and G. Chon and P. R. Christensen and E. Churazov and D. L. Clements and S. Colafrancesco and L. P. L. Colombo and A. Coulais and B. P. Crill and F. Cuttaia and A. Da Silva and H. Dahle and L. Danese and R. J. Davis and P. de Bernardis and G. de Gasperis and A. de Rosa and G. de Zotti and J. Delabrouille and J. Démoclès and F. -X. Désert and C. Dickinson and J. M. Diego and K. Dolag and H. Dole and S. Donzelli and O. Doré and U. Dörl and M. Douspis and X. Dupac and T. A. Enßlin and H. K. Eriksen and F. Finelli and I. Flores-Cacho and O. Forni and M. Frailis and E. Franceschi and M. Frommert and S. Galeotta and K. Ganga and R. T. Génova-Santos and M. Giard and M. Gilfanov and J. González-Nuevo and K. M. Górski and A. Gregorio and A. Gruppuso and F. K. Hansen and D. Harrison and S. Henrot-Versillé and C. Hernández-Monteagudo and S. R. Hildebrandt and E. Hivon and M. Hobson and W. A. Holmes and A. Hornstrup and W. Hovest and K. M. Huffenberger and G. Hurier and T. R. Jaffe and T. Jagemann and W. C. Jones and M. Juvela and E. Keihänen and I. Khamitov and R. Kneissl and J. Knoche and L. Knox and M. Kunz and H. Kurki-Suonio and G. Lagache and A. Lähteenmäki and J. -M. Lamarre and A. Lasenby and C. R. Lawrence and M. Le Jeune and R. Leonardi and P. B. Lilje and M. Linden-Vørnle and M. López-Caniego and P. M. Lubin and J. F. Macías-Pérez and B. Maffei and D. Maino and N. Mandolesi and M. Maris and F. Marleau and E. Martínez-González and S. Masi and M. Massardi and S. Matarrese and F. Matthai and P. Mazzotta and S. Mei and A. Melchiorri and J. -B. Melin and L. Mendes and A. Mennella and S. Mitra and M. -A. Miville-Deschênes and A. Moneti and L. Montier and G. Morgante and D. Munshi and J. A. Murphy and P. Naselsky and P. Natoli and H. U. Nørgaard-Nielsen and F. Noviello and D. Novikov and I. Novikov and S. Osborne and F. Pajot and D. Paoletti and O. Perdereau and F. Perrotta and F. Piacentini and M. Piat and E. Pierpaoli and R. Piffaretti and S. Plaszczynski and E. Pointecouteau and G. Polenta and N. Ponthieu and L. Popa and T. Poutanen and G. W. Pratt and S. Prunet and J. -L. Puget and J. P. Rachen and R. Rebolo and M. Reinecke and M. Remazeilles and C. Renault and S. Ricciardi and T. Riller and I. Ristorcelli and G. Rocha and M. Roman and C. Rosset and M. Rossetti and J. A. Rubiño-Martín and L. Rudnick and B. Rusholme and M. Sandri and G. Savini and B. M. Schaefer and D. Scott and G. F. Smoot and F. Stivoli and R. Sudiwala and R. Sunyaev and D. Sutton and A. -S. Suur-Uski and J. -F. Sygnet and J. A. Tauber and L. Terenzi and L. Toffolatti and M. Tomasi and M. Tristram and J. Tuovinen and M. Türler and G. Umana and L. Valenziano and B. Van Tent and J. Varis and P. Vielva and F. Villa and N. Vittorio and L. A. Wade and B. D. Wandelt and N. Welikala and S. D. M. White and D. Yvon and A. Zacchei and S. Zaroubi and A. Zonca},
journal= {arXiv preprint arXiv:1208.3611},
year = {2015}
}
Comments
20 pages, 18 figure, accepted by A&A, replaced to match published version