Planck intermediate results. VIII. Filaments between interacting clusters
Abstract
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. 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. 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 select physical pairs of clusters as candidates. Using the Planck data we construct a local map of the tSZ effect centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray maps of these pairs. After having modelled and subtracted the tSZ effect and X-ray emission for each cluster in the pair we study the residuals on both the SZ and X-ray maps. 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)x10^-4, cm^-3. The Planck satellite mission has provided the first SZ detection of the hot and diffuse intercluster gas.
Cite
@article{arxiv.1208.5911,
title = {Planck intermediate results. VIII. Filaments between interacting clusters},
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 R. Bhatia and I. Bikmaev and H. Böhringer and A. Bonaldi and J. R. Bond and J. Borrill and F. R. Bouchet and H. Bourdin and R. Burenin and C. Burigana and P. Cabella and J. -F. Cardoso and G. Castex and A. Catalano and L. Cayón and A. Chamballu and R. -R. Chary and L. -Y Chiang and G. Chon and P. R. Christensen and D. L. Clements and S. Colafrancesco and L. P. L. Colombo and B. Comis 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 G. de Zotti and J. Delabrouille and J. Démoclès and F. -X. Désert 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 G. Efstathiou 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 Y. Giraud-Héraud and J. González-Nuevo and K. M. Górski and A. Gregorio and A. Gruppuso and F. K. Hansen and D. Harrison and A. Hempel and S. Henrot-Versillé and C. Hernández-Monteagudo and D. Herranz and S. R. Hildebrandt and E. Hivon and M. Hobson and W. A. Holmes and W. Hovest and G. Hurier and T. R. Jaffe and A. H. Jaffe and T. Jagemann and W. C. Jones and M. Juvela and I. Khamitov and T. S. Kisner and R. Kneissl and J. Knoche and L. Knox and M. Kunz and H. Kurki-Suonio and G. Lagache 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 G. Luzzi and J. F. Macías-Pérez and B. Maffei and D. Maino and N. Mandolesi and M. Maris and F. Marleau and D. J. Marshall 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 F. Nati 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 F. Pasian and G. Patanchon and O. Perdereau and L. Perotto 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 B. Rusholme and M. Sandri and G. Savini and B. M. Schaefer and D. Scott and G. F. Smoot and J. -L. Starck 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 L. Valenziano and B. Van Tent 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 A. Zonca},
journal= {arXiv preprint arXiv:1208.5911},
year = {2015}
}
Comments
Accepted by A&A