### Abstract

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_{ν}) and 16 X-ray Y_{X} measurements of sample clusters, we simultaneously calibrate themass-observable relation and constrain cosmological parameters. Ourmethod accounts for cluster selection, cosmological sensitivity, and uncertainties in the mass calibrators. The calibrations using σ_{ν}and Y_{X} are consistent at the 0.6σ level, with the σ_{ν} calibration preferring ∼16% higher masses. We use the full SPTCL data set (SZ clusters+σ_{ν}+Y_{X}) to measure σ_{8} (Ω_{m}/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 Σ 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 Σm_{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_{ν}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 Ω_{m} = 0.299 ± 0.009 and σ_{8} = 0.829 ± 0.011. Within a νCDM model we find Σm_{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).

Original language | English (US) |
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Article number | 214 |

Journal | Astrophysical Journal |

Volume | 799 |

Issue number | 2 |

DOIs | |

State | Published - Feb 1 2015 |

### Keywords

- Cosmic background radiation
- Cosmology: observations
- Galaxies: clusters: individual
- Large-scale structure of universe

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

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## Cite this

_{ν}and X-ray Y

_{X}measurements.

*Astrophysical Journal*,

*799*(2), [214]. https://doi.org/10.1088/0004-637X/799/2/214