Biased cosmological parameter estimation with galaxy cluster counts in the presence of primordial non-Gaussianities,
_{NL}.For many years, inflation has been the most widely accepted model to explain the density perturbations observed in the universe and the most simple inflation models consider that the initial density perturbations presented a Gaussian distribution. This assumption seems to be in overall agreement with current observational data but many inflationary models present, instead, a certain degree of non-gaussianity, with potentially observable consequences for this different distribution. As a way to narrow down the list of inflation models compatible with the observational data, it is mandatory to determine which would be the observable consequences of different levels of non-gaussianity in the initial density perturbations. In order to achieve this, three major observational quantities were considered: the present-day dark energy density, the dark energy equation of state parameter and the present-day root mean square mass perturbations at the 8 h These quantities were estimated for 5 different levels of non-gaussianity assuming a flat ΛCDM fiducial cosmological model and an observed sky area of 4000 deg The results obtained show a modest bias arising in the present-day dark energy density and in the dark energy equation of state parameter from considering Gaussian perturbations in the case they had, in fact, a level of non-gaussianity. However, for the present-day root mean square mass perturbations, the bias is significantly larger (Fig. 1). Even so, excluding the fiducial value for this quantity with 2σ significance would require a level of non-gaussianity of about -80 or significantly above 100. Although the results obtained from the Planck satellite data ensure the local level of non-gaussianity is very small (2.7±5.8), this could be a function of scale and there is actually some evidence that at cluster scales this parameter may have a value of about -240. Thus, this work demonstrates it is important to consider the effect of non-gaussianity in the estimation of the present-day root mean square mass perturbations. |