Optimal weights for measuring redshift space distortions in multitracer galaxy catalogues

David W. Pearson*, Lado Samushia, Praful Gagrani

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

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Abstract

Since the volume accessible to galaxy surveys is fundamentally limited, it is extremely important to analyse available data in the most optimal fashion. One way of enhancing the cosmological information extracted from the clustering of galaxies is by weighting the galaxy field. The most widely used weighting schemes assign weights to galaxies based on the average local density in the region (FKP weights) and their bias with respect to the dark matter field (PVP weights). They are designed to minimize the fractional variance of the galaxy power-spectrum. We demonstrate that the currently used bias dependent weighting scheme can be further optimized for specific cosmological parameters. We develop a procedure for computing the optimal weights and test them against mock catalogues for which the values of all fitting parameters, as well as the input power-spectrum are known. We show that by applying these weights to the joint power-spectrum of emission line galaxies and luminous red galaxies from the Dark Energy Spectroscopic Instrument survey, the variance in the measured growth rate parameter can be reduced by as much as 36 per cent.

Original languageEnglish
Pages (from-to)2708-2715
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Volume463
Issue number3
Early online date30 Aug 2016
DOIs
Publication statusPublished - Dec 2016

Keywords

  • Cosmological parameters
  • Galaxies: statistics
  • Large-scale structure of universe
  • Methods: data analysis

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