Enhancing Bispectrum Estimators for Galaxy Redshift Surveys with Velocities

Abstract

We forecast the ability of bispectrum estimators to constrain primordial non-Gaussianity using future photometric galaxy redshift surveys. A full-sky survey with photometric redshift resolution of $\sigma_z/(1+z)=0.05$ in the redshift range $0.2<z<2$ can provide constraints $\sigma(f^\mathrm{local}_\mathrm{NL})=3.4$, $\sigma(f^\mathrm{equil}_\mathrm{NL})=15$, and $\sigma(f^\mathrm{orth}_\mathrm{NL})=17$ for the local, equilateral, and orthogonal shapes respectively, delivering constraints on primordial non-Gaussianities competitive to those from the cosmic microwave background. We generalize these results by deriving a scaling relation for the constraints on the amplitude of primordial non-Gaussianity as a function of redshift error, depth, sky coverage, and nonlinear scale cutoff. Finally, we investigate the impact that photometric calibration errors on the largest scales will have on the constraining power of future experiments. We show that peculiar velocities reconstructed via kinetic Sunyaev Zeldovich tomography can be used to mitigate the impact of calibration errors on primordial non-Gaussianity constraints.