http://arxiv.org/abs/2002.09904
Clustering of the large scale structure provides complementary information to the measurements of the cosmic microwave background anisotropies through power spectrum and bispectrum of density perturbations. Extracting the bispectrum information, however, is more challenging than it is from the power spectrum due to the complex models and the computational cost to measure the signal and its covariance. To overcome these problems, we adopt a proxy statistic, skew spectrum which is a cross-spectrum of the density field and its quadratic field. By applying a large smoothing filter to the density field, we show our theory fits the simulations very well. With the spectra and their covariance form $N$-body simulations as our “mock” Universe, we perform a global fits on the cosmological parameters. The results show a slight sub-Poisson shot noise, and by adding skew spectrum to power spectrum, the $1\sigma$ marginalized errors for $ b_1^2A_s, n_s$ and $f_{\rm NL}^{\rm loc}$ are reduced by $34\%, 22\%, 46\%$, respectively. The skew spectrum will be an effective method to study the complementary information to those from the power spectrum measurements, especially with the forthcoming generation of wide-field galaxy surveys.
J. Dai, L. Verde and J. Xia
Tue, 25 Feb 20
31/76
Comments: 18 pages, 8 figures, submitted to JCAP
You must be logged in to post a comment.