Constraints on shear and rotation with massive galaxy clusters

Ahmad Mehrabi, Francesco Pace, Mohammad Malekjani, Antonino Del Popolo

    Research output: Contribution to journalArticlepeer-review


    A precise determination of the mass function is an important tool to verify cosmological predictions of the λ cold dark matter (CDM) model and to infer more precisely the better model describing the evolution of the Universe. Galaxy clusters have been currently used to infer cosmological parameters, in particular thematter density parameter Ωm, the matter power spectrum normalization σ8 and the equation of state parameter wde of the dark energy fluid. In this work, using data on massive galaxy clusters (M > 8 × 1014 h-1M ) in the redshift range 0.05 ≲ z ≲ 0.83, for the first time we put constraints on the parameter α introduced within the formalism of the extended spherical collapse model to quantify deviations from sphericity due to shear and rotation. Since at the moment there is no physical model describing its functional shape, we assume it to be a logarithmic function of the cluster mass. By holding σ8 fixed and restricting our analysis to a ΛCDM model, we find, at 1σ confidence level, Ω m = 0.284 ± 0.0064, h = 0.678 ± 0.017 and β = 0.0019-0.0015 +0.0008, where β represents the slope of the parameter a. This result translates into a 9 per cent decrement of the number of massive clusters with respect to a standard λ CDM mass function, but better data are required to better constrain this quantity, since at the 2σ and 3σ confidence level we are only able to infer upper limits.

    Original languageEnglish
    Pages (from-to)2687-2697
    Number of pages11
    JournalMonthly Notices of the Royal Astronomical Society
    Issue number3
    Early online date14 Nov 2016
    Publication statusPublished - Mar 2017


    • Cosmology: theory
    • Dark energy
    • Methods: analytical
    • Methods: statistical


    Dive into the research topics of 'Constraints on shear and rotation with massive galaxy clusters'. Together they form a unique fingerprint.

    Cite this