CODEX: Role of velocity substructure in the scaling relations of galaxy clusters

S. Damsted; A. Finoguenov; N. Clerc; I. Davalgaite; C. C. Kirkpatrick; G. A. Mamon; J. Ider Chitham; K. Kiiveri; J. Comparat; C. Collins

arXiv · 2307.08749

CODEX: Role of velocity substructure in the scaling relations of galaxy clusters

S. Damsted·A. Finoguenov·N. Clerc·I. Davalgaite·C. C. Kirkpatrick·G. A. Mamon·J. Ider Chitham·K. Kiiveri·J. Comparat·C. Collins

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Abstract

The use of galaxy clusters as cosmological probes relies on a detailed understanding of their properties. We aim to update the spectroscopic cluster identification of CODEX by running the spectroscopic group finder on the follow-up spectroscopy results and connecting the dynamical state of clusters to their scaling relations. We implemented a reproducible spectroscopic membership determination and cleaning procedures, based on the redMaPPer membership, running the spectroscopic group finder on the follow-up spectroscopy results and cleaning the membership for spectroscopic outliers. We applied the Anderson-Darling test for velocity substructure and analysed its influence on the scaling relations. We also tested the effect of the X-ray-to-optical centre offset on the scaling relations. We report on the scaling relations between richness, X-ray luminosity, and velocity dispersion for a complete sample of clusters with at least 15 members. Clusters with velocity substructure exhibit enhanced velocity dispersion for a given richness and are characterized by 2.5 times larger scatter. Clusters that have a strong offset in X-ray-to-optical centres have comparable scaling relations as clusters with substructure. We demonstrate that there is a consistency in the parameters of the scaling relations for the low- and high-richness galaxy clusters. Splitting the clusters by redshift, we note a decrease in scatter with redshift in all scaling relations. We localize the redshift range where a high scatter is observed to $z<0.15$, which is in agreement with the literature results on the scatter. We note that the increase in scatter for both high- and low-luminosity clusters is $z<0.15$, suggesting that both cooling and the resulting active galactic nucleus feedback are at the root of this scatter. Abridged.

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S. Damsted, A. Finoguenov, N. Clerc, I. Davalgaite, C. C. Kirkpatrick, G. A. Mamon, J. Ider Chitham, K. Kiiveri, J. Comparat, C. Collins. 2023-07-17. CODEX: Role of velocity substructure in the scaling relations of galaxy clusters. https://arxiv.org/abs/2307.08749

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