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arXiv · 1503.04467

A Consistency Relation for the Observed Galaxy Bispectrum and the Local non-Gaussianity from Relativistic Corrections

A. Kehagias·A. Moradinezhad Dizgah·J. Noreña·H. Perrier·A. Riotto
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Abstract

We obtain a consistency relation for the observed three-point correlator of galaxies. It includes relativistic effects and it is valid in the squeezed limit. Furthermore, the consistency relation is non-perturbative and can be used at arbitrarily small scales for the short modes. Our results are also useful to compute the non-linear relativistic corrections which induce a signal in the observations that might be misinterpreted as primordial non-Gaussianity with a local shape. We estimate the effective local non-Gaussianity parameter from the relativistic corrections. The exact value depends on the redshift and the magnification bias. At redshift of $ z = 1$, in the absence of magnification bias, we get $\,\, f^{\rm GR}_{\rm NL} \simeq - 3.7 $.

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A. Kehagias, A. Moradinezhad Dizgah, J. Noreña, H. Perrier, A. Riotto. 2015-07-28. A Consistency Relation for the Observed Galaxy Bispectrum and the Local non-Gaussianity from Relativistic Corrections. https://doi.org/10.1088/1475-7516%2F2015%2F08%2F018

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