Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion σ v and X-Ray Y X Measurements

• Published in: The Astrophysical Journal
• Main Authors: Bocquet S, Saro A, Mohr J J, Aird K A, Ashby M L N, Bautz M, Bayliss M, Bazin G, Benson B A, Bleem L E, Brodwin M, Carlstrom J E, Chang C L, Chiu I, Cho H M, Clocchiatti A, Crawford T M, Crites A T, Desai S, de Haan T, Dietrich J P, Dobbs M A, Foley R J, Forman W R, Gangkofner D, George E M, Gladders M D, Gonzalez A H, Halverson N W, Hennig C, Hlavacek-Larrondo J, Holder G P, Holzapfel W L, Hrubes J D, Jones C, Keisler R, Knox L, Lee A T, Leitch E M, Liu J, Lueker M, Luong-Van D, Marrone D P, McDonald M, McMahon J J, Meyer S S, Mocanu L, Murray S S, Padin S, Pryke C, Reichardt C L, Rest A, Ruel J, Ruhl J E, Saliwanchik B R, Sayre J T, Schaffer K K, Shirokoff E, Spieler H G, Stalder B, Stanford S A, Staniszewski Z, Stark A A, Story K, Stubbs C W, Vanderlinde K, Vieira J D, Vikhlinin A, Williamson R, Zahn O, Zenteno A
• Other Authors: Bocquet, S, Saro, A, Mohr, J J, Aird, K A, Ashby, M L N, Bautz, M, Bayliss, M, Bazin, G, Benson, B A, Bleem, L E, Brodwin, M, Carlstrom, J E, Chang, C L, Chiu, I, Cho, H M, Clocchiatti, A, Crawford, T M, Crites, A T, Desai, S, de Haan, T, Dietrich, J P, Dobbs, M A, Foley, R J, Forman, W R, Gangkofner, D, George, E M, Gladders, M D, Gonzalez, A H, Halverson, N W, Hennig, C, Hlavacek-Larrondo, J, Holder, G P, Holzapfel, W L, Hrubes, J D, Jones, C, Keisler, R, Knox, L, Lee, A T, Leitch, E M, Liu, J, Lueker, M, Luong-Van, D, Marrone, D P, Mcdonald, M, Mcmahon, J J, Meyer, S S, Mocanu, L, Murray, S S, Padin, S, Pryke, C
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2015
• Subjects: cosmic background radiation; cosmology: observation; galaxies: clusters: individual; large-scale structure of universe; Astrophysics - Cosmology and Nongalactic Astrophysics; South Pole; The ''Y''; South pole
• Online Access: http://hdl.handle.net/11368/2962565; https://doi.org/10.1088/0004-637X/799/2/214; https://iopscience.iop.org/article/10.1088/0004-637X/799/2/214

We present a velocity-dispersion-based mass calibration of the South Pole Telescope Sunyaev-Zel'dovich effect survey (SPT-SZ) galaxy cluster sample. Using a homogeneously selected sample of 100 cluster candidates from 720 deg2 of the survey along with 63 velocity dispersion (σ v ) and 16 X-ray Y X measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. Our method accounts for cluster selection, cosmological sensitivity, and uncertainties in the mass calibrators. The calibrations using σ v and Y X are consistent at the 0.6σ level, with the σ v calibration preferring ~16% higher masses. We use the full SPTCL data set (SZ clusters+σ v +Y X) to measure σ8(Ωm/0.27)0.3 = 0.809 ± 0.036 within a flat ΛCDM model. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming that the sum of the neutrino masses is ∑m ν = 0.06 eV, we find the data sets to be consistent at the 1.0σ level for WMAP9 and 1.5σ for Planck+WP. Allowing for larger ∑m ν further reconciles the results. When we combine the SPTCL and Planck+WP data sets with information from baryon acoustic oscillations and Type Ia supernovae, the preferred cluster masses are 1.9σ higher than the Y X calibration and 0.8σ higher than the σ v calibration. Given the scale of these shifts (~44% and ~23% in mass, respectively), we execute a goodness-of-fit test; it reveals no tension, indicating that the best-fit model provides an adequate description of the data. Using the multi-probe data set, we measure Ωm = 0.299 ± 0.009 and σ8 = 0.829 ± 0.011. Within a νCDM model we find ∑m ν = 0.148 ± 0.081 eV. We present a consistency test of the cosmic growth rate using SPT clusters. Allowing both the growth index γ and the dark energy equation-of-state parameter w to vary, we find γ = 0.73 ± 0.28 and w = -1.007 ± 0.065, demonstrating that the expansion and the growth histories are consistent with a ΛCDM universe (γ = 0.55; w = -1).