ACT-DR5 Sunyaev-Zel’dovich clusters: Weak lensing mass calibration with KiDS

Vol. 681
3. Cosmology (including clusters of galaxies)

ACT-DR5 Sunyaev-Zel’dovich clusters: Weak lensing mass calibration with KiDS

Galaxy clusters trace the large-scale matter distribution in the Universe. It is fundamental to know precisely their number density, masses, baryon content, and evolution with redshift, to reveal the growth of structure and constrain the amplitude of matter fluctuations, the matter density, and the dark energy equation of state. They are important diagnostics of any cosmological model, and can test the standard LCDM model. The present work has measured the mass of 157 clusters within the Kilo Degree Survey (KiDS), with weak gravitational lensing (WL). These clusters were also clearly detected by the thermal Sunyaev-Zel’dovich (SZ) effect with the Atacama Cosmology Telescope (ACT). It is expected that the WL masses are higher than the SZ ones, since they are sensitive to the total mass, independent of the cluster dynamical state. The SZ cluster mass estimate MSZ, calibrated using X-ray observations, is biased with MSZ/MWL = (1 - bSZ) = 0.65 ± 0.05. This bias value bSZ does not depend on the cluster mass. This bias value is compatible with the predictions from the Planck cosmic microwave background LCDM cosmological model. This agreement is in contrast with previous measurements, as shown in the figure.