The observed galaxy bispectrum from single-field inflation in the squeezed limit
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing
Abstract
Using the consistency relation in Fourier space, we derive the observed galaxy bispectrum from
single- eld in
ation 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 e ective non-
Gaussianity due to general-relativistic lightcone e ects that could mimic a primordial non-Gaussian
signal.
Description
Keywords
Fourier space, Galaxy, Galaxy bispectrum, Single-fi eld inflation
Citation
Koyama, K. et al. (2018). The observed galaxy bispectrum from single- eld in ation in the squeezed limit. Journal of Cosmology and Astroparticle Physics, 20180: 050