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

Kazuya Koyama, Obinna Umeh, Roy Maartens, Daniele Bertacca

Institute of Cosmology & Gravitation

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Abstract

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

Keywords

astro-ph.CO
gr-qc
hep-th
RCUK
STFC
ST/N000668/1

Access to Document

10.1088/1475-7516/2018/07/050

1805.09189v2
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.
Accepted author manuscript (Post-print), 657 KB

Data availability statement for 'The observed galaxy bispectrum from single-field inflation in the squeezed limit'.
Koyama, K. (Creator), Umeh, O. (Creator), Maartens, R. (Creator) & Bertacca, D. (Creator), University of Portsmouth, 23 Jul 2018
Dataset

Cosmological Tests of Gravity
Koyama, K.
European Research Council
1/09/15 → 31/08/20
Project: Research

Space telescope to test Einstein's theories about gravity
Kazuya Koyama
19/09/18 → 5/10/18
1 item of Media coverage, 1 Media contribution
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Cite this

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AU - Umeh, Obinna

AU - Maartens, Roy

AU - Bertacca, Daniele

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JF - Journal of Cosmology and Astroparticle Physics

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ER -

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

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Data availability statement for 'The observed galaxy bispectrum from single-field inflation in the squeezed limit'.

Projects

Cosmological Tests of Gravity

Press/Media

Space telescope to test Einstein's theories about gravity

Cite this