The effect of dynamical states on galaxy cluster populations

II. Comparison of galaxy properties and fundamental relations

¹ Departamento de Astronomía, Universidad de La Serena, Av. Raúl Bitrán 1305, La Serena, Chile
² International Gemini Observatory, NFS NOIRLab, Casilla 603, La Serena, Chile
³ Cerro Tololo Inter-American Observatory, NFS NOIRLab, Casilla 603, La Serena, Chile

^⋆ Corresponding author: simon.veliz@userena.cl

Received: 17 April 2025
Accepted: 12 August 2025

Abstract

Context. Galaxy clusters provide a unique environment in which to study the influence of extreme conditions on galaxy evolution. The role of cluster dynamical states in shaping the physical and morphological properties of member galaxies remains an open question.

Aims. We aim to assess the impact of the dynamical state of massive (M₅₀₀ ≥ 1.5 × 10¹⁴ M_⊙) galaxy clusters on the physical and structural properties of their member galaxies, and also in their fundamental relations in the redshift range 0.10 < z < 0.35, comparing relaxed and disturbed clusters.

Methods. We use a mass-matched sample of galaxies from relaxed and disturbed clusters. Morphological types were assigned using both parametric and nonparametric methods, while physical properties were derived through spectral energy distribution fitting. Galaxies were further divided into subpopulations based on their colors and stellar masses to investigate trends with cluster dynamical states. Additionally, we examined correlations between the dynamical state of clusters and their fundamental relations, such as color-magnitude, mass-size, morphology-density, and SF-density relations.

Results. The dynamical state of galaxy clusters does not alter their fundamental relations at low redshift, nor does it significantly affect the mean or dispersion of galaxy properties. However, it does impact the distributions at the level of third- and fourth-order moments, introducing asymmetries and heavier tails in the structural parameters and specific star formation rates (sSFRs) of galaxies. The greatest effects are observed in the sSFRs of low-mass and red sequence galaxies.

Conclusions. These findings suggest that, at low redshift, the fundamental relations of massive galaxy clusters are already well established and resilient to recent dynamical activity. Nonetheless, the influence of the dynamical state on the higher-order moments of galaxy properties indicates that environmental processes associated with disturbed clusters – such as tidal interactions, ram-pressure stripping, and harassment – still leave measurable imprints, particularly on low-mass and red sequence galaxies. This is consistent with the idea that galaxy evolution is shaped both by early pre-processing and by subsequent interactions within dynamically active environments.