The observed galaxy bispectrum from single-field inflation in the squeezed limit

Kazuya Koyama; Obinna Umeh; Roy Maartens; Daniele Bertacca

doi:10.1088/1475-7516/2018/07/050

The observed galaxy bispectrum from single-field inflation in the squeezed limit

Research output: Contribution to journal › Article

Institute of Cosmology & Gravitation

Using the consistency relation in Fourier space, we derive the observed galaxy bispectrum from single-field inflation in the squeezed limit, in which one of the three modes has a wavelength much longer than the other two. This provides a non-trivial check of the full computation of the bispectrum based on second-order cosmological perturbation theory in this limit. We show that gauge modes need to be carefully removed in the second-order cosmological perturbations in order to calculate the observed galaxy bispectrum in the squeezed limit. We then give an estimate of the effective non-Gaussianity due to general relativistic lightcone effects that could mimic a primordial non-Gaussian signal.

Original language	English
Article number	050
Number of pages	20
Journal	Journal of Cosmology and Astroparticle Physics
Volume	2018
Issue number	07
DOIs	https://doi.org/10.1088/1475-7516/2018/07/050
Publication status	Published - 23 Jul 2018

Documents

1805.09189v2
Rights statement: This is an author-created, un-copyedited version of an article published in Journal of Cosmology and Astroparticle Physics. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1475-7516/2018/07/050.
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