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Title: DISCOVERY OF A SUPERCLUSTER AT z ∼ 0.91 AND TESTING THE ΛCDM COSMOLOGICAL MODEL

The ΛCDM cosmological model successfully reproduces many aspects of the galaxy and structure formation of the universe. However, the growth of large-scale structures (LSSs) in the early universe is not well tested yet with observational data. Here, we have utilized wide and deep optical–near-infrared data in order to search for distant galaxy clusters and superclusters (0.8 < z < 1.2). From the spectroscopic observation with the Inamori Magellan Areal Camera and Spectrograph (IMACS) on the Magellan telescope, three massive clusters at z ∼ 0.91 are confirmed in the SSA22 field. Interestingly, all of them have similar redshifts within Δ z ∼ 0.01 with velocity dispersions ranging from 470 to 1300 km s{sup −1}. Moreover, as the maximum separation is ∼15 Mpc, they compose a supercluster at z ∼ 0.91, meaning that this is one of the most massive superclusters at this redshift to date. The galaxy density map implies that the confirmed clusters are embedded in a larger structure stretching over ∼100 Mpc. ΛCDM models predict about one supercluster like this in our surveyed volume, consistent with our finding so far. However, there are more supercluster candidates in this field, suggesting that additional studies are required to determine if the ΛCDM cosmological model can successfully reproducemore » the LSSs at high redshift.« less
Authors:
; ; ; ; ; ; ; ; ;  [1] ;  [2] ; ; ; ;  [3] ;  [4] ;  [5]
  1. Center for the Exploration of the Origin of the universe, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
  2. Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom)
  3. Astronomy Program, FPRD, Department of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of)
  4. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A’ohoku Place, Hilo, HI 96720 (United States)
  5. Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of)
Publication Date:
OSTI Identifier:
22518487
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 821; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CAMERAS; COSMOLOGICAL CONSTANT; COSMOLOGICAL MODELS; COSMOLOGY; DENSITY; GALAXIES; GALAXY CLUSTERS; NEAR INFRARED RADIATION; RED SHIFT; TELESCOPES; UNIVERSE