DOE OSTI · 3007070
Window convolution of the galaxy clustering bispectrum
Abstract
In galaxy survey analysis, the observed clustering statistics do not directly match theoretical predictions but rather have been processed by a window function that arises from the survey geometry including the sky footprint, redshift-dependent background number density and systematic weights. While window convolution of the power spectrum is well studied, for the bispectrum with a larger number of degrees of freedom, it poses a significant numerical and computational challenge. In this work, we consider the effect of the survey window in the tripolar spherical harmonic decomposition of the bispectrum and lay down a formal procedure for their convolution via a series expansion of configuration-space three-point correlation functions, which was first proposed by Sugiyama et al. (2019). We then provide a linear algebra formulation of the full window convolution, where an unwindowed bispectrum model vector can be directly premultiplied by a window matrix specific to each survey geometry. To validate the pipeline, we focus on the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) luminous red galaxy (LRG) sample in the South Galactic Cap (SGC) in the redshift bin 0.4 ≤ z ≤ 0.6. We first perform convergence checks on the measurement of the window function from discrete random catalogues, and then investigate the convergence of the window convolution series expansion truncated at a finite of number of terms as well as the performance of the window matrix. This work highlights the differences in window convolution between the power spectrum and bispectrum, and provides a streamlined pipeline for the latter for current surveys such as DESI and the Euclid mission.
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Wang, M. S. [Univ. of Edinburgh, Scotland (United Kingdom)] (ORCID:0000000226524043), Beutler, F. [Univ. of Edinburgh, Scotland (United Kingdom)] (ORCID:0000000304675438), Aguilar, J. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Ahlen, S. [Boston Univ., MA (United States)] (ORCID:0000000160987247), Bianchi, D. [Univ. degli Studi di Milano (Italy)] (ORCID:0000000197120006), Brooks, D. [Univ. College London (United Kingdom)], Claybaugh, T. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], de la Macorra, A. [Univ. Nacional Autonoma de Mexico (UNAM), Mexico City (Mexico)] (ORCID:0000000217691640), Doel, P. [Univ. College London (United Kingdom)], Font-Ribera, A. [Univ. Autonoma de Barcelona (Spain). Inst. de Fisica d'Altes Energies (IFAE); Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona (Spain)] (ORCID:0000000230337312), Gaztañaga, E. [Institut d'Estudis Espacials de Catalunya (IEEC), Barcelona (Spain); Univ. of Portsmouth (United Kingdom); Institute of Space Sciences, Barcelona (Spain)], Gutierrez, G. [Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States)], Honscheid, K. [The Ohio State Univ., Columbus, OH (United States)] (ORCID:0000000265502023), Howlett, C. [Univ. of Queensland, Brisbane, QLD (Australia)] (ORCID:0000000210819410), Kirkby, D. [Univ. of California, Irvine, CA (United States)] (ORCID:0000000288285463), Lambert, A. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Landriau, M. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)] (ORCID:0000000318388528), Miquel, R. [Univ. Autonoma de Barcelona (Spain). Inst. Catalana de Recerca i Estudis Avancats (ICREA) and Inst. de Fisica d'Altes Energies (IFAE)], Niz, G. [Univ. of Guanajuato (Mexico); Inst. for Advanced Cosmology (Mexico)] (ORCID:0000000215448946), Prada, F. [Institute of Astrophysics of Andalusia (Spain)] (ORCID:0000000171458674), Pérez-Ràfols, I. [Univ. Politecnica de Catalunya (Spain)] (ORCID:0000000169790125), Rossi, G. [Sejong Univ., Seoul (Korea, Republic of)], Sanchez, E. [Research Centre for Energy, Environment and Technology (CIEMAT), Madrid (Spain)] (ORCID:0000000296468198), Schlegel, D. [Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)], Schubnell, M. [Univ. of Michigan, Ann Arbor, MI (United States)], Sprayberry, D. [National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)], Tarlé, G. [Univ. of Michigan, Ann Arbor, MI (United States)] (ORCID:0000000317040781), Weaver, B. A. [National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Tucson, AZ (United States)]. 2025-06-18. Window convolution of the galaxy clustering bispectrum. https://doi.org/10.1088/1475-7516%2F2025%2F06%2F031
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