Mass Calibration and Cosmological Analysis of the SPT-SZ Galaxy Cluster Sample Using Velocity Dispersion $σ_v$ and X-ray $Y_\textrm{X}$ Measurements

• 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.
• Format: Text
• Language: unknown
• Published: arXiv 2014
• Subjects: Cosmology and Nongalactic Astrophysics astro-ph.CO; FOS Physical sciences; South Pole; South pole
• Online Access: https://dx.doi.org/10.48550/arxiv.1407.2942; https://arxiv.org/abs/1407.2942

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 Yx measurements of sample clusters, we simultaneously calibrate the mass-observable relation and constrain cosmological parameters. The calibrations using $σ_v$ and Yx are consistent at the $0.6σ$ level, with the $σ_v$ calibration preferring ~16% higher masses. We use the full cluster dataset to measure $σ_8(Ω_ m/0.27)^{0.3}=0.809\pm0.036$. The SPT cluster abundance is lower than preferred by either the WMAP9 or Planck+WMAP9 polarization (WP) data, but assuming the sum of the neutrino masses is $\sum m_ν=0.06$ eV, we find the datasets to be consistent at the 1.0$σ$ level for WMAP9 and 1.5$σ$ for Planck+WP. Allowing for larger $\sum m_ν$ further reconciles the results. When we combine the cluster and Planck+WP datasets with BAO and SNIa, the preferred cluster masses are $1.9σ$ higher than the Yx 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 dataset, we measure $Ω_ m=0.299\pm0.009$ and $σ_8=0.829\pm0.011$. Within a $ν$CDM model we find $\sum m_ν= 0.148\pm0.081$ eV. We present a consistency test of the cosmic growth rate. Allowing both the growth index $γ$ and the dark energy equation of state parameter $w$ to vary, we find $γ=0.73\pm0.28$ and $w=-1.007\pm0.065$, demonstrating that the expansion and the growth histories are consistent with a LCDM model ($γ=0.55; \,w=-1$). : Accepted by ApJ (v2 is accepted version); 17 pages, 6 figures