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A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups

Dvornik, Andrej; Cacciato, Marcello; Kuijken, Konrad; Viola, Massimo; Hoekstra, Henk; Nakajima, Reiko; van Uitert, Edo; Brouwer, Margot; Choi, Ami; Erben, Thomas; Fenech Conti, Ian; Farrow, Daniel J.; Herbonnet, Ricardo; Heymans, Catherine; Hildebrandt, Hendrik; Hopkins, Andrew M.; McFarland, John; Norberg, Peder; Schneider, Peter; Sifón, Cristóbal; Valentijn, Edwin; Wang, Lingyu

A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups Thumbnail


Andrej Dvornik

Marcello Cacciato

Konrad Kuijken

Massimo Viola

Henk Hoekstra

Reiko Nakajima

Edo van Uitert

Margot Brouwer

Ami Choi

Thomas Erben

Ian Fenech Conti

Daniel J. Farrow

Ricardo Herbonnet

Catherine Heymans

Hendrik Hildebrandt

Andrew M. Hopkins

John McFarland

Peter Schneider

Cristóbal Sifón

Edwin Valentijn

Lingyu Wang


We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the Galaxy And Mass Assembly (GAMA) survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality photometric Kilo-Degree Survey.We use GAMA groups with an apparent richness larger than 4 to identify samples with comparable mean host halo masses but with a different radial distribution of satellite galaxies, which is a proxy for the formation time of the haloes. We measure the weak lensing signal for groups with a steeper than average and with a shallower than average satellite distribution and find no sign of halo assembly bias, with the bias ratio of 0.85+0.37 −0.25, which is consistent with the cold dark matter prediction. Our galaxy groups have typical masses of 1013M h−1, naturally complementing previous studies of halo assembly bias on galaxy cluster scales.


Dvornik, A., Cacciato, M., Kuijken, K., Viola, M., Hoekstra, H., Nakajima, R., …Wang, L. (2017). A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups. Monthly Notices of the Royal Astronomical Society, 468(3), 3251-3265.

Journal Article Type Article
Acceptance Date Mar 20, 2017
Online Publication Date Mar 22, 2017
Publication Date Mar 22, 2017
Deposit Date Jul 5, 2017
Publicly Available Date Jul 5, 2017
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 468
Issue 3
Pages 3251-3265


Published Journal Article (2.5 Mb)

Copyright Statement
© 2017 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.

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