We investigate possible signatures of halo assembly bias for spectroscopically selected galaxy groups from the GAMA survey using weak lensing measurements from the spatially overlapping regions of the deeper, high-imaging-quality photometric KiDS 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 0.85−0.25+0.37, which is consistent with the ΛCDM prediction. Our galaxy groups have typical masses of 1013M⊙/h, naturally complementing previous studies of halo assembly bias on galaxy cluster scales.
@article{arxiv.1703.06657,
title = {A KiDS weak lensing analysis of assembly bias in GAMA galaxy groups},
author = {Andrej Dvornik and Marcello Cacciato and Konrad Kuijken and Massimo Viola and Henk Hoekstra and Reiko Nakajima and Edo van Uitert and Margot Brouwer and Ami Choi and Thomas Erben and Ian Fenech Conti and Daniel J. Farrow and Ricardo Herbonnet and Catherine Heymans and Hendrik Hildebrandt and Andrew. M. Hopkins and John McFarland and Peder Norberg and Peter Schneider and Cristóbal Sifón and Edwin Valentijn and Lingyu Wang},
journal= {arXiv preprint arXiv:1703.06657},
year = {2017}
}