Origin of the delayed anti-correlation in dynamical-state measurements

Determine whether the delayed anti-correlation between dynamical-state parameter measurements and earlier mass-accretion measurements is a physical feature of galaxy-cluster evolution, an artifact of the simulations, or a quirk of the dynamical-state parameters used in the analysis.

Background

The paper identifies a blue arc below the diagonal in the correlation heatmaps of mass-accretion history and dynamical-state parameters. This feature represents a systematic anti-correlation in which dynamical-state measurements taken at a later time are related to mass measurements from an earlier epoch.

The authors state that the physical interpretation of this feature is unresolved. Clarifying its origin is important for determining whether the apparent time-lagged signal reflects genuine cluster dynamics or instead arises from simulation artifacts or the particular definitions of the virial ratio, center-of-mass offset, and substructure mass fraction.