ACT-DR5 Sunyaev-Zel'dovich Clusters: weak lensing mass calibration with KiDS

Abstract

We present weak gravitational lensing measurements of a sample of 157 clusters within the Kilo Degree Survey (KiDS), detected with a $>5\ddot{I}ƒ$ thermal Sunyaev-Zel'dovich (SZ) signal by the Atacama Cosmology Telescope (ACT). Using a halo-model approach we constrain the average total cluster mass, $M_{\mathrm{WL}}$, accounting for the ACT cluster selection function of the full sample. We find that the SZ cluster mass estimate $M_{\mathrm{SZ}}$, which was calibrated using X-ray observations, is biased with $M_{\mathrm{SZ}}/M_{\mathrm{WL}}=(1-b_{\mathrm{SZ}})=0.65\pm 0.05$. Separating the sample into six mass bins, we find no evidence of a strong mass-dependency for the mass bias, $(1-b_{\mathrm{SZ}})$. Adopting this ACT-KiDS SZ mass-calibration would bring the Planck SZ cluster count into agreement with the counts expected from the {\it Planck} cosmic microwave background $\hat{I}›$CDM cosmological model, although it should be noted that the cluster sample considered in this work has a lower average mass $M_{\mathrm{SZ},\mathrm{uncor}}=3.64\times 10^{14}{M}_{\odot }$ compared to the Planck cluster sample which has an average mass in the range $M_{\mathrm{SZ},\mathrm{uncor}}=(5.5-8.5)\times 10^{14}{M}_{\odot }$, depending on the sub-sample used.

12 pages, 7 figures