| Issue |
A&A
Volume 540, April 2012
|
|
|---|---|---|
| Article Number | A60 | |
| Number of page(s) | 8 | |
| Section | Numerical methods and codes | |
| DOI | https://doi.org/10.1051/0004-6361/201118463 | |
| Published online | 27 March 2012 | |
3DEX: a code for fast spherical Fourier-Bessel decomposition of 3D surveys⋆
1 Department of Physics and Astronomy, University College London, London WC1E 6BT, UK
e-mail: boris.leistedt@gmail.com
2 Laboratoire d’Astrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire de Sauverny, 1290 Versoix, Switzerland
e-mail: anais.rassat@epfl.ch
3 Institute for Astronomy, ETH Zürich, Wolfgang-Pauli-Strasse 27, 8093 Zürich, Swtitzerland
4 Laboratoire AIM, UMR CEA-CNRS-Paris 7, Irfu, SAp/SEDI, Service d’Astrophysique, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
Received: 15 November 2011
Accepted: 6 February 2012
Context. High-precision cosmology requires the analysis of large-scale surveys in 3D spherical coordinates, i.e. spherical Fourier-Bessel decomposition. Current methods are insufficient for future data-sets from wide-field cosmology surveys.
Aims. The aim of this paper is to present a public code for fast spherical Fourier-Bessel decomposition that can be applied to cosmological data or 3D data in spherical coordinates in other scientific fields.
Methods. We present an equivalent formulation of the spherical Fourier-Bessel decomposition that separates radial and tangential calculations. We propose to use the existing pixelisation scheme HEALPix for a rapid calculation of the tangential modes.
Results. 3DEX (3D EXpansions) is a public code for fast spherical Fourier-Bessel decomposition of 3D all-sky surveys that takes advantage of HEALPix for the calculation of tangential modes. We perform tests on very large simulations and we compare the precision and computation time of our method with an optimised implementation of the spherical Fourier-Bessel original formulation. For surveys with millions of galaxies, computation time is reduced by a factor 4–12 depending on the desired scales and accuracy. The formulation is also suitable for pre-calculations and external storage of the spherical harmonics, which allows for additional speed improvements. The 3DEX code can accommodate data with masked regions of missing data. 3DEX can also be used in other disciplines, where 3D data are to be analysed in spherical coordinates.
Key words: cosmology: observations / large-scale structure of Universe / methods: statistical / methods: data analysis / galaxies: statistics
The code and documentation can be downloaded at http://ixkael.com/blog/3dex
© ESO, 2012
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.