Anson D'Aloisio, Priyamvada Natarajan
In a recently published article, we quantified the impact of primordial
non-Gaussianity on the probability of giant-arc formation. In that work, we
focused on the local form of non-Gaussianity and found that it can have only a
modest effect given the most recent constraints from Cosmic Microwave
Background (CMB) measurements. Here, we present new calculations using a
parameterization of scale-dependent non-Gaussianity in which the primordial
bispectrum has the equilateral shape and the effective f_NL parameter depends
on scale. We find that non-Gaussianity of this type can yield a larger effect
on the giant-arc abundance compared to the local form due to both the scale
dependence and the relatively weaker constraints on the equilateral shape from
CMB measurements. In contrast to the maximum ~40% effect (within the latest CMB
constraints) previously found for the local form, we find that the predicted
giant-arc abundance for the scale-dependent equilateral form can differ by a
factor of a few with respect to the Gaussian case.
View original:
http://arxiv.org/abs/1202.0553
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