New Fast Algorithm for Computing Bispectrum Multipoles in Cosmological Data
Researchers have developed an FFT-based estimator that rapidly computes angular multipoles of the redshift space bispectrum, a key statistical measure in cosmology. The new method reduces computational time from O(N_g^6) to O(N_g^4), making analysis of large 3D cosmological fields significantly faster. This advancement could enhance the scientific return from galaxy surveys and future 21-cm observations by extracting previously underutilized directional information.
A new computational method has been proposed to efficiently calculate the angular multipole moments of the bispectrum—a three-point correlation function used to study the large-scale structure of the universe. The bispectrum's dependence on triangle orientation relative to the line of sight contains valuable cosmological information, quantified through angular multipoles B_ℓ^m. The researchers developed an FFT-based estimator that computes all multipole moments, including previously neglected off-diagonal terms (m≠0), with dramatically improved computational efficiency. Validation using simulated non-Gaussian fields showed excellent agreement with analytical predictions across all 16 non-zero multipoles up to ℓ=6, m=6. The authors argue that including the m≠0 multipoles could substantially increase the information extracted from upcoming galaxy redshift surveys and 21-cm intensity mapping observations.
What different sources said
- arXiv astro-phCenter
Brisk estimator for the angular multipoles of the redshift space bispectrum
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