Exploring the contamination of the DES-Y1 cluster sample with SPT-SZ selected clusters

Grandis, S; Mohr, JJ; Costanzi, M; Saro, A; Bocquet, S; Klein, M; Aguena, M; Allam, S; Annis, J; Ansarinejad, B; Bacon, D; Bertin, E; Bleem, L; Brooks, D; Burke, DL; Carnero Rosel, A; Carrasco Kind, M; Carretero, J; Castander, FJ; Choi, A; da Costa, LN; De Vincente, J; Desai, S; Diehl, HT; Dietrich, JP; Doel, P; Eifler, TF; Everett, S; Ferrero, I; Floyd, B; Fosalba, P; Frieman, J; García-Bellido, J; Gaztanaga, E; Gruen, D; Gruendl, RA; Gschwend, J; Gupta, N; Gutierrez, G; Hinton, SR; Hollowood, DL; Honscheid, K; James, DJ; Jeltema, T; Kuehn, K; Lahav, O; Lidman, C; Lima, M; Maia, MAG; March, M; Marshall, JL; Melchior, P; Menanteau, F; Miquel, R; Morgan, R; Myles, J; Ogando, R; Palmese, A; Paz-Chinchón, F; Plazas, AA; Reichardt, CL; Romer, AK; Sanchez, E; Scarpine, V; Serrano, S; Sevilla-Noarbe, I; Singh, P; Smith, M; Suchyta, E; Swanson, MEC; Tarle, G; Thomas, D; To, C; Weller, J; Wilkinson, RD; Wu, H

doi:10.1093/mnras/stab869

Exploring the contamination of the DES-Y1 cluster sample with SPT-SZ selected clusters

Grandis, S; Mohr, JJ; Costanzi, M; Saro, A; Bocquet, S; Klein, M; Aguena, M; Allam, S; Annis, J; Ansarinejad, B; Bacon, D; Bertin, E; Bleem, L; Brooks, D; Burke, DL; Carnero Rosel, A; Carrasco Kind, M; Carretero, J; Castander, FJ; Choi, A; da Costa, LN; De Vincente, J; Desai, S; Diehl, HT; Dietrich, JP; Doel, P; Eifler, TF; Everett, S; Ferrero, I; Floyd, B; Fosalba, P; Frieman, J; García-Bellido, J; Gaztanaga, E; Gruen, D; Gruendl, RA; Gschwend, J; Gupta, N; Gutierrez, G; Hinton, SR; Hollowood, DL; Honscheid, K; James, DJ; Jeltema, T; Kuehn, K; Lahav, O; Lidman, C; Lima, M; Maia, MAG; March, M; Marshall, JL; Melchior, P; Menanteau, F; Miquel, R; Morgan, R; Myles, J; Ogando, R; Palmese, A; Paz-Chinchón, F; Plazas, AA; Reichardt, CL; Romer, AK; Sanchez, E; Scarpine, V; Serrano, S; Sevilla-Noarbe, I; Singh, P; Smith, M; Suchyta, E; Swanson, MEC; Tarle, G; Thomas, D; To, C; Weller, J; Wilkinson, RD; Wu, H

Authors

S Grandis

JJ Mohr

M Costanzi

A Saro

S Bocquet

M Klein

M Aguena

S Allam

J Annis

B Ansarinejad

D Bacon

E Bertin

L Bleem

D Brooks

DL Burke

A Carnero Rosel

M Carrasco Kind

J Carretero

FJ Castander

A Choi

LN da Costa

J De Vincente

S Desai

HT Diehl

JP Dietrich

P Doel

TF Eifler

S Everett

I Ferrero

B Floyd

P Fosalba

J Frieman

J García-Bellido

E Gaztanaga

D Gruen

RA Gruendl

J Gschwend

N Gupta

G Gutierrez

SR Hinton

DL Hollowood

K Honscheid

DJ James

T Jeltema

K Kuehn

O Lahav

C Lidman

M Lima

MAG Maia

M March

JL Marshall

P Melchior

F Menanteau

R Miquel

R Morgan

J Myles

R Ogando

A Palmese

F Paz-Chinchón

AA Plazas

CL Reichardt

AK Romer

E Sanchez

V Scarpine

S Serrano

I Sevilla-Noarbe

P Singh

M Smith

E Suchyta

MEC Swanson

G Tarle

D Thomas

C To

J Weller

RD Wilkinson

H Wu

Abstract

We perform a cross validation of the cluster catalogue selected by the red-sequence Matched-filter Probabilistic Percolation algorithm (redMaPPer) in Dark Energy Survey year 1 (DES-Y1) data by matching it with the Sunyaev–Zel’dovich effect (SZE) selected cluster catalogue from the South Pole Telescope SPT-SZ survey. Of the 1005 redMaPPer selected clusters with measured richness λ^>40 in the joint footprint, 207 are confirmed by SPT-SZ. Using the mass information from the SZE signal, we calibrate the richness–mass relation using a Bayesian cluster population model. We find a mass trend λ ∝ MB consistent with a linear relation (B ∼ 1), no significant redshift evolution and an intrinsic scatter in richness of σλ = 0.22 ± 0.06. By considering two error models, we explore the impact of projection effects on the richness–mass modelling, confirming that such effects are not detectable at the current level of systematic uncertainties. At low richness SPT-SZ confirms fewer redMaPPer clusters than expected. We interpret this richness dependent deficit in confirmed systems as due to the increased presence at low richness of low-mass objects not correctly accounted for by our richness-mass scatter model, which we call contaminants. At a richness λ^=40⁠, this population makes up >12 per cent (97.5 percentile) of the total population. Extrapolating this to a measured richness λ^=20 yields >22 per cent (97.5 percentile). With these contamination fractions, the predicted redMaPPer number counts in different plausible cosmologies are compatible with the measured abundance. The presence of such a population is also a plausible explanation for the different mass trends (B ∼ 0.75) obtained from mass calibration using purely optically selected clusters. The mean mass from stacked weak lensing (WL) measurements suggests that these low-mass contaminants are galaxy groups with masses ∼3–5 × 1013 M⊙ which are beyond the sensitivity of current SZE and X-ray surveys but a natural target for SPT-3G and eROSITA.

Citation

Grandis, S., Mohr, J., Costanzi, M., Saro, A., Bocquet, S., Klein, M., …Wu, H. (2021). Exploring the contamination of the DES-Y1 cluster sample with SPT-SZ selected clusters. Monthly Notices of the Royal Astronomical Society, 504(1), 1253-1272. https://doi.org/10.1093/mnras/stab869

Journal Article Type	Article
Acceptance Date	Mar 19, 2021
Online Publication Date	Mar 25, 2021
Publication Date	2021-06
Deposit Date	Nov 16, 2021
Publicly Available Date	Nov 16, 2021
Journal	Monthly Notices of the Royal Astronomical Society
Print ISSN	0035-8711
Electronic ISSN	1365-2966
Publisher	Royal Astronomical Society
Peer Reviewed	Peer Reviewed
Volume	504
Issue	1
Pages	1253-1272
DOI	https://doi.org/10.1093/mnras/stab869

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Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2021 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.