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Dark Energy Survey Year 1 results: validation of weak lensing cluster member contamination estimates from P(z) decomposition

Varga, TN; DeRose, J; Gruen, D; McClintock, T; Seitz, S; Rozo, E; Costanzi, M; ... Zhang, Y; + view all (2019) Dark Energy Survey Year 1 results: validation of weak lensing cluster member contamination estimates from P(z) decomposition. Monthly Notices of the Royal Astronomical Society , 489 (2) pp. 2511-2524. 10.1093/mnras/stz2185. Green open access

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Abstract

Weak lensing source galaxy catalogues used in estimating the masses of galaxy clusters can be heavily contaminated by cluster members, prohibiting accurate mass calibration. In this study, we test the performance of an estimator for the extent of cluster member contamination based on decomposing the photometric redshift P(z) of source galaxies into contaminating and background components. We perform a full scale mock analysis on a simulated sky survey approximately mirroring the observational properties of the Dark Energy Survey Year One observations (DES Y1), and find excellent agreement between the true number profile of contaminating cluster member galaxies in the simulation and the estimated one. We further apply the method to estimate the cluster member contamination for the DES Y1 redMaPPer cluster mass calibration analysis, and compare the results to an alternative approach based on the angular correlation of weak lensing source galaxies. We find indications that the correlation based estimates are biased by the selection of the weak lensing sources in the cluster vicinity, which does not strongly impact the P(z) decomposition method. Collectively, these benchmarks demonstrate the strength of the P(z) decomposition method in alleviating membership contamination and enabling highly accurate cluster weak lensing studies without broad exclusion of source galaxies, thereby improving the total constraining power of cluster mass calibration via weak lensing.

Type: Article
Title: Dark Energy Survey Year 1 results: validation of weak lensing cluster member contamination estimates from P(z) decomposition
Open access status: An open access version is available from UCL Discovery
DOI: 10.1093/mnras/stz2185
Publisher version: https://doi.org/10.1093/mnras/stz2185
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: gravitational lensing: weak, galaxies: clusters: general, cosmology: observations
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10084323
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