2016/08/31 by Saroj Adhikari, Donghui Jeong, Sarah Shandera · 9 citations
Mathematics · Physics and Astronomy · #Amplitude #Anisotropy #Astrophysics #Astrophysics and Cosmic Phenomena #Bicoherence #Bispectrum #Cosmic microwave background #Cosmic variance #Cosmology and Gravitation Theories #Equilateral triangle #Galaxies: Formation, Evolution, Phenomena #Geometry #Mathematics #Measure (data warehouse) #Non-Gaussianity #Physics #Position (finance) #Quantum mechanics #Spectral density #Statistical physics #Statistics #Trispectrum #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.94.083528
published in Physical review. D/Physical review. D. 94(8) (American Physical Society) · 5 figures, 2 tables; v2: small changes to match the PRD version
openalex created_date 2016/09/16 · openalex publication_date 2016/10/31 · arxiv created 2016/11/01 · arxiv updated 2016/11/02 · openalex updated_date 2026/08/06
We develop and study the position-dependent bispectrum. It is a generalization of the recently proposed position-dependent power spectrum method of measuring the squeezed-limit bispectrum. The position-dependent bispectrum can similarly be used to measure the squeezed-limit trispectrum in which one of the wavelengths is much longer than the other three. In this work, we will mainly consider the case in which the three smaller wavelengths are nearly the same (the equilateral configuration). We use the Fisher information matrix to forecast constraints on bias parameters and the amplitude of primordial trispectra from the position-dependent bispectrum method. We find that the method can constrain the local-type gNL at a level of \ensuremathσ(gNLlocal)\ensuremath≈3\ifmmode×\else\texttimes\fi105 for a large volume SPHEREx-like survey; improvements can be expected by including all the triangular configurations of the bispectra rather than just the equilateral configuration. However, the same measurement would also constrain a much larger family of trispectra than local gNL model. We discuss the implications of the forecasted reach of future surveys in terms of super cosmic variance uncertainties from primordial non-Gaussianities.