DISCOVERY AND COSMOLOGICAL IMPLICATIONS OF SPT-CL J2106-5844, THE MOST MASSIVE KNOWN CLUSTER AT z > 1

作者：Foley R J^*; Andersson K; Bazin G; de Haan T; Ruel J; Ade P A R; Aird K A; Armstrong R; Ashby M L N; Bautz M; Benson B A; Bleem L E; Bonamente M; Brodwin M; Carlstrom J E; Chang C L; Clocchiatti A; Crawford T M; Crites A T; Desai S; Dobbs M A; Dudley J P; Fazio G G; Forman W R; Garmire G; George E M; Gladders M D; Gonzalez A H; Halverson N W; High F W; Holder G P; Holzapfel W L; Hoover S; Hrubes J D

来源：Astrophysical Journal, 2011, 731(2): 86.

DOI：10.1088/0004-637X/731/2/86

• early universe
• galaxies: clusters: individual (SPT-CL J2106-5844)
• galaxies: evolution
• galaxies: formation
• large-scale structure of universe

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(-0.003)(+0.002). 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 T-X = 11.0(-1.9)(+2.6) keV and a luminosity (within r(500)) of L-X(0.5-2.0 keV) = (13.9 +/- 1.0) x 10(44) erg s(-1). The combined mass estimate from measurements of the SZ effect and X-ray data is M-200 = (1.27 +/- 0.21) x 10(15) h(70)(-1) M-circle dot. The discovery of such amassive 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 Lambda CDM 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 deg(2) SPT survey region and that only one such galaxy cluster is expected in the entire sky.

• 出版日期2011-4-20
• 单位MIT; McGill