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

Abstract

Weak lensing source galaxy catalogs 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 ofmore » source galaxies, thereby improving the total constraining power of cluster mass calibration via weak lensing.« less

Authors:
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States); SLAC National Accelerator Lab., Menlo Park, CA (United States); Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
Contributing Org.:
DES
OSTI Identifier:
1490843
Report Number(s):
arXiv:1812.05116; FERMILAB-PUB-18-681-AE
1708933
DOE Contract Number:  
AC02-07CH11359
Resource Type:
Journal Article
Journal Name:
TBD
Additional Journal Information:
Journal Name: TBD
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS

Citation Formats

Varga, T. N., and et al. Dark Energy Survey Year 1 results: Validation of weak lensing cluster member contamination estimates from $P(z)$ decomposition. United States: N. p., 2018. Web.
Varga, T. N., & et al. Dark Energy Survey Year 1 results: Validation of weak lensing cluster member contamination estimates from $P(z)$ decomposition. United States.
Varga, T. N., and et al. Wed . "Dark Energy Survey Year 1 results: Validation of weak lensing cluster member contamination estimates from $P(z)$ decomposition". United States. https://www.osti.gov/servlets/purl/1490843.
@article{osti_1490843,
title = {Dark Energy Survey Year 1 results: Validation of weak lensing cluster member contamination estimates from $P(z)$ decomposition},
author = {Varga, T. N. and et al.},
abstractNote = {Weak lensing source galaxy catalogs 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.},
doi = {},
journal = {TBD},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:

Figures / Tables:

Figure 1 Figure 1: $(Left$ $panels$:) P(z) decomposition at three different radial ranges for the cluster sample with richness λ ∈ [30; 45) and redshift z ∈ [0.2; 0.35) in DES Y1 data. Black lines: average weighted P(z | R) of source galaxies. Red lines: P(z) of the Gaussian contamination component scaledmore » by the estimated cluster member contamination rate fcl. $Magenta$ $lines$: average P(z | field) scaled by 1 – fcl. $Blue$ $dashed$: model P(z) calculated from the sum of the magenta and red lines. The vertical dashed lines indicate the redshift range of galaxy clusters in the cluster selection. ($Right$ $panel$:) the cluster member contamination rate fcl profile calculated from the decomposition presented on the left panels: the red shaded range corresponds to the amplitudes of the Gaussian components at each radial range. The width of the shaded area indicates the 1σ uncertainty region.« less

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Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.