A generalized local ansatz and its effect on halo bias

Sarah Shandera, Neal Dalal, Dragan Huterer

Research output: Contribution to journalArticle

Abstract

Motivated by the properties of early universe scenarios that produce observationally large local non-Gaussianity, we perform N-body simulations with non-Gaussian initial conditions from a generalized local ansatz. The bispectra are schematically of the local shape, but with scale-dependent amplitude. We find that in such cases the size of the non-Gaussian correction to the bias of small and large mass objects depends on the amplitude of non-Gaussianity roughly on the scale of the object. In addition, some forms of the generalized bispectrum alter the scale dependence of the non-Gaussian term in the bias by a fractional power of k. These features may allow significant observational constraints on the particle physics origin of any observed local non-Gaussianity, distinguishing between scenarios where a single field or multiple fields contribute to the curvature fluctuations. While analytic predictions for the non-Gaussian bias agree qualitatively with the simulations, we find numerically a stronger observational signal than expected. This suggests that a more precise understanding of halo formation is needed to fully explain the consequences of primordial non-Gaussianity.

Original languageEnglish (US)
Article number017
JournalJournal of Cosmology and Astroparticle Physics
Volume2011
Issue number3
DOIs
StatePublished - Mar 2011

Keywords

  • cosmological simulations
  • ination
  • non-gaussianity

ASJC Scopus subject areas

  • Astronomy and Astrophysics

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