Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132+0.002 -0.003. Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of TX = 11.0+2.6 -1.9 keV and a luminosity (within r 500) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 1044 erg s-1. The combined mass estimate from measurements of the SZ effect and X-ray data is M 200 = (1.27 ± 0.21) × 1015 h -1 70 M sun. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg2 SPT survey region and that only one such galaxy cluster is expected in the entire sky.
A Sunyaev-Zel'dovich-selected sample of the most massive galaxy clusters in the 2500 deg 2 South Pole telescope survey / Williamson, R.; Benson, B. A.; High, F. W.; Vanderlinde, K.; Ade, P. A. R.; Aird, K. A.; Andersson, K.; Armstrong, R.; Ashby, M. L. N.; Bautz, M.; Bazin, G.; Bertin, E.; Bleem, L. E.; Bonamente, M.; Brodwin, M.; Carlstrom, J. E.; Chang, C. L.; Chapman, S. C.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; Dehaan, T.; Desai, S.; Dobbs, M. A.; Dudley, J. P.; Fazio, G. G.; Foley, R. J.; Forman, W. R.; Garmire, G.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Halverson, N. W.; Holder, G. P.; Holzapfel, W. L.; Hoover, S.; Hrubes, J. D.; Jones, C.; Joy, M.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; Lueker, M.; Luong-Van, D.; Marrone, D. P.; Mcmahon, J. J.; Mehl, J.; Meyer, S. S.; Mohr, J. J.; Montroy, T. E.; Murray, S. S.; Padin, S.; Plagge, T.; Pryke, C.; Reichardt, C. L.; Rest, A.; Ruel, J.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Schaffer, K. K.; Shaw, L.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K.; Stubbs, C. W.; Vieira, J. D.; Vikhlinin, A.; Zenteno, A.. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 738:2(2011), pp. 139.139-139.-. [10.1088/0004-637X/738/2/139]
A Sunyaev-Zel'dovich-selected sample of the most massive galaxy clusters in the 2500 deg 2 South Pole telescope survey
Saro, A.;
2011-01-01
Abstract
Using the South Pole Telescope (SPT), we have discovered the most massive known galaxy cluster at z>1, SPT-CL J2106-5844. In addition to producing a strong Sunyaev-Zel'dovich (SZ) effect signal, this system is a luminous X-ray source and its numerous constituent galaxies display spatial and color clustering, all indicating the presence of a massive galaxy cluster. Very Large Telescope and Magellan spectroscopy of 18 member galaxies shows that the cluster is at z = 1.132+0.002 -0.003. Chandra observations obtained through a combined HRC-ACIS GTO program reveal an X-ray spectrum with an Fe K line redshifted by z = 1.18 ± 0.03. These redshifts are consistent with the galaxy colors found in optical, near-infrared, and mid-infrared imaging. SPT-CL J2106-5844 displays extreme X-ray properties for a cluster having a core-excluded temperature of TX = 11.0+2.6 -1.9 keV and a luminosity (within r 500) of LX (0.5-2.0 keV) = (13.9 ± 1.0) × 1044 erg s-1. The combined mass estimate from measurements of the SZ effect and X-ray data is M 200 = (1.27 ± 0.21) × 1015 h -1 70 M sun. The discovery of such a massive gravitationally collapsed system at high redshift provides an interesting laboratory for galaxy formation and evolution, and is a probe of extreme perturbations of the primordial matter density field. We discuss the latter, determining that, under the assumption of ΛCDM cosmology with only Gaussian perturbations, there is only a 7% chance of finding a galaxy cluster similar to SPT-CL J2106-5844 in the 2500 deg2 SPT survey region and that only one such galaxy cluster is expected in the entire sky.Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
