Constraints on Primordial Non-Gaussianity Using the Multitracer Technique for Skew Spectra

Abstract

Extracting the bispectrum information from large-scale structure observations is challenging due to the complex models and the computational costs involved in measuring the signal and its covariance. Recently, the skew spectrum was proposed to access parts of the bispectrum information in a more effective manner and was confirmed to provide complementary information to that available in power spectrum measurements. In this work, we generalize the theory to apply the multitracer technique and explore its ability to constrain the local-type primordial non-Gaussianity. Using the spectra and their covariance estimated from N -body simulations, we find that the multitracer approach is effective in reducing the cosmic variance noise. The 1 σ marginalized errors for , and are reduced by 50%, 52%, and 73% compared with the results achieved using only the power spectrum obtained from a single tracer. These results indicate that both the skew spectrum and the multitracer technique are useful in constraining the primordial non-Gaussianity with the forthcoming wide-field galaxy surveys.