Scale-dependent non-Gaussianity and the CMB Power Asymmetry

Original · EN

We introduce an alternative parametrisation for the scale dependence of the non-linearity parameter f NL in quasi-local models of non-Gaussianity. Our parametrisation remains valid when f NL changes sign, unlike the commonly adopted power law ansatz f NL(k) ∝ knf NL. We motivate our alternative parametrisation by appealing to the self-interacting curvaton scenario, and as an application, we apply it to the CMB power asymmetry. Explaining the power asymmetry requires a strongly scale dependent non-Gaussianity. We show that regimes of model parameter space where f NL is strongly scale dependent are typically associated with a large g NL and quadrupolar power asymmetry, which can be ruled out by existing observational constraints.