Implications for primordial non-Gaussianity (fNL) from weak lensing masses of high-z galaxy clusters

Abstract

The recent weak-lensing measurement of the dark matter mass of the high-redshift galaxy cluster XMMUJ2235.3-2557 of ( 8.5 ± 1.7 ) × 10 14 M ⊙ at z = 1.4 , indicates that, if the cluster is assumed to be the result of the collapse of dark matter in a primordial Gaussian field in the standard lambda cold dark matter model, then its abundance should be < 2 × 10 − 3 clusters in the observed area. Here we investigate how to boost the probability of XMMUJ2235.3-2557, in particular, resorting to deviations from Gaussian initial conditions. We show that this abundance can be boosted by factors > 3 - 10 if the non-Gaussianity parameter f local NL is in the range 150-200. This value is comparable to the limit for f NL obtained by current constraints from the cosmic microwave background. We conclude that mass determination of high-redshift, massive clusters can offer a complementary probe of primordial non-Gaussianity.