Constraining equilateral-type primordial non-Gaussianities from imaging surveys

Understand

We investigate expected constraints on equilateral-type primordial non-Gaussianities from future/ongoing imaging surveys, making use of the fact that they enhance the halo/galaxy bispectrum on large scales.

• As model parameters to be constrained, in addition to $f_{\rm NL}^{\rm equil}$, which is related to the primordial bispectrum, we consider $g_{\rm NL}^{(\partial \sigma)^4}$, which is related to the primordial trispectrum that appeared in the effective field theory of inflation.
• After calculating the angular bispectra of the halo/galaxy clustering and weak gravitational lensing based on the integrated perturbation theory, we perform Fisher matrix analysis for three representative surveys.
• We find that among the three surveys, the tightest constraints come from Large Synoptic Survey Telescope ; its expected $1\sigma$ errors on $f_{\rm NL}^{\rm equil}$ and $g_{\rm NL}^{(\partial \sigma)^4}$ are respectively given by $7.0 \times 10^2$ and $4.9 \times 10^7$.