## Abstract

*M*and SZ signal Y calibrated to X-ray measurements, we derive constraints on the power spectrum amplitude σ

_{8}and matter density parameter Ωm in a flat ΛCDM model. We test the robustness of our estimates and find that possible biases in the

*Y–M*relation and the halo mass function are larger than the statistical uncertainties from the cluster sample. Assuming the X-ray determined mass to be biased low relative to the true mass by between zero and 30%, motivated by comparison of the observed mass scaling relations to those from a set of numerical simulations, we find that σ

_{8}= 0.75 ± 0.03, Ω

_{m}= 0.29 ± 0.02, and σ

_{8}(Ω=0.27)

^{0.3}= 0.764 ± 0.025. The value of 8 is degenerate with the mass bias; if the latter is fixed to a value of 20% (the central value from numerical simulations) we find σ8 (Ω

_{m}/0.27)

^{0.3}= 0.78 ± 0.01 and a tighter one-dimensional range σ

_{8}= 0.77± 0.02. We find that the larger values of σ

_{8}and Ω

_{m}preferred by

*Planck’s*measurements of the primary CMB anisotropies can be accommodated by a mass bias of about 40%. Alternatively, consistency with the primary CMB constraints can be achieved by inclusion of processes that suppress power on small scales relative to the CDM model, such as a component of massive neutrinos. We place our results in the context of other determinations of cosmological parameters, and discuss issues that need to be resolved in order to make further progress in this field.

Original language | English |
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Article number | A20 |

Journal | Astronomy and Astrophysics |

Volume | 571 |

Number of pages | 20 |

ISSN | 0004-6361 |

DOIs | |

Publication status | Published - 2013 |

## Keywords

- Cosmological parameters
- Large-scale structure of Universe
- Galaxies: clusters: general