Galaxy Skew-Spectra in Redshift-Space

Abstract

Modern galaxy surveys focus on the galaxy power spectrum or 2-point correlation function to test and constrain cosmological models. Additional information comes from higher-order N-point functions, but their analysis is challenging. A simple solution is to compute the cross-power spectrum between the squared galaxy density and the galaxy density. Being simple to measure and to plot, this skew-spectrum shares many of the familiar useful properties of the standard galaxy power spectrum. We show that by computing multiple quadratic fields and correlating them with the density, all contributions to the tree-level redshift-space galaxy bispectrum can be captured with skew-spectra. Using synthetic datasets, we show that our measurement pipeline matches analytical predictions, and that their dependence on galaxy bias parameters and the logarithmic growth rate is as expected theoretically.

arXiv comment13 pages, 4 figures, code available at https://github.com/mschmittfull/skewspec

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• Analytic Gaussian Covariance Matrices for Galaxy $N$-Point Correlation Functions
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• Cosmology with Persistent Homology: a Fisher Forecast
• Skewing the CMB$\times$LSS: a Fast Method for Bispectrum Analysis
• Weak Lensing Trispectrum and Kurt-Spectra
• The Compressed 3D Lyman-Alpha Forest Bispectrum
• Cosmology with Persistent Homology: Parameter Inference via Machine Learning