Imperial College London
Portrait Picture

Dr Jonathan R. Pritchard

Faculty of Natural Sciences, Department of Physics

Reader in Astrophysics
 
 
 
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Contact

 

+44 (0)20 7594 7557j.pritchard Website CV

 
 
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Location

 

1018CBlackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Watkinson:2017:mnras/stx2130,
author = {Watkinson, CA and Majumdar, S and Pritchard, JR and Mondal, R},
doi = {mnras/stx2130},
journal = {Monthly Notices of the Royal Astronomical Society},
pages = {2436--2446},
title = {A fast estimator for the bispectrum and beyond - a practical method for measuring non-Gaussianity in 21-cm maps},
url = {http://dx.doi.org/10.1093/mnras/stx2130},
volume = {472},
year = {2017}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - In this paper, we establish the accuracy and robustness of a fast estimator for the bispectrum – the ‘FFT-bispectrum estimator’. The implementation of the estimator presented here offers speed and simplicity benefits over a direct-measurement approach. We also generalize the derivation so it may be easily be applied to any order polyspectra, such as the trispectrum, with the cost of only a handful of Fast-Fourier Transforms (FFTs). All lower order statistics can also be calculated simultaneously for little extra cost. To test the estimator, we make use of a non-linear density field, and for a more strongly non-Gaussian test case, we use a toy-model of reionization in which ionized bubbles at a given redshift are all of equal size and are randomly distributed. Our tests find that the FFT-estimator remains accurate over a wide range of k, and so should be extremely useful for analysis of 21-cm observations. The speed of the FFT-bispectrum estimator makes it suitable for sampling applications, such as Bayesian inference. The algorithm we describe should prove valuable in the analysis of simulations and observations, and whilst, we apply it within the field of cosmology, this estimator is useful in any field that deals with non-Gaussian data.
AU  - Watkinson,CA
AU  - Majumdar,S
AU  - Pritchard,JR
AU  - Mondal,R
DO  - mnras/stx2130
EP  - 2446
PY  - 2017///
SN  - 0035-8711
SP  - 2436
TI  - A fast estimator for the bispectrum and beyond - a practical method for measuring non-Gaussianity in 21-cm maps
T2  - Monthly Notices of the Royal Astronomical Society
UR  - http://dx.doi.org/10.1093/mnras/stx2130
UR  - http://hdl.handle.net/10044/1/56831
VL  - 472
ER  -
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