Scale-dependent bias due to primordial vector fields

Abstract

Anisotropic stress perturbations induced by primordial Gaussian vector fields create non-Gaussianity in curvature perturbations. We found that such non-Gaussianity closely resembles the local-type non-Gaussianity parametrized by $f_{\mathrm{NL}}$, and generates scale-dependent bias in large-scale structures. We also found a simple relationship between the scale-dependent bias and the power spectrum of the vector fields. When the vector fields are interpreted as primordial magnetic fields, the effective $f_{\mathrm{NL}}$ is shown to be always negative. The scale-dependent bias provides a new approach to probing primordial vector fields.

9 pages, 5 figures. Accepted for publication in MNRAS Mon.Not.Roy.Astron.Soc. (2013)

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• δN Formalism in Anisotropic Inflation and Large Anisotropic Bispectrum and Trispectrum
• Anisotropic Inflation with the non-Vacuum Initial State
• Primordial Anisotropies in Gauged Hybrid Inflation
• Large Scale Anisotropic Bias from Primordial non-Gaussianity
• Scale and shape dependent non-Gaussianity in the presence of inflationary vector fields