A measurement of cluster masses using Planck and SPT-SZ CMB lensing

Université Paris-Saclay, CEA, Département de Physique des Particules, 91191 Gif-sur-Yvette, France

Received: 28 February 2024
Accepted: 17 June 2024

Abstract

We used an unbiased cosmic microwave background (CMB) lensing mass estimator on 468 SPT-SZ clusters from the SPT-SZ and the Planck public data. We measured the average ratio between CMB lensing and the SZ masses to be 〈M_CMBlens/M_SZ〉 = 0.98 ± 0.19 (stat.) ± 0.03 (syst.). The average CMB lensing mass from the combination of the two datasets is measured at 4.8σ, which is a significant gain with respect to the measurement performed on the SPT-SZ-only (3.9σ) or the Planck-only (3.7σ) dataset. We showed that the combination not only takes advantage of the two different ranges of spatial scales (i.e. Fourier modes) observed but also exploits the lensing-induced correlation between scales observed by one experiment and the other. This result demonstrates the importance of measuring a large range of spatial scales for CMB lensing mass estimation, from arcmins to degrees. This large range of scales will most probably be provided by the combination of various datasets, such as from the large- and small-aperture telescopes of the upcoming Simons Observatory and future CMB-S4 experiment, and Planck. In this context, the Planck temperature data will remain a key element of CMB lensing cluster studies in the years to come.