Quantifying the statistics of CMB-lensing-derived galaxy cluster mass measurements with simulations

Abstract

CMB lensing is a promising, novel way to measure galaxy cluster masses that can be used, e.g., for mass calibration in galaxy cluster counts analyses. Understanding the statistics of the galaxy cluster mass observable obtained with such measurements is essential if their use in subsequent analyses is not to lead to biased results. We study the statistics of a CMB lensing galaxy cluster mass observable for a Planck-like experiment with mock observations obtained from an N-body simulation. We quantify the bias and intrinsic scatter associated with this observable following two different approaches, one in which the signal due to the cluster and nearby correlated large-scale structure is isolated, and another one in which the variation due to uncorrelated large-scale structure is also taken into account. For our first approach we also quantify deviations from log-normality in the scatter, finding them to have a negligible impact on mass calibration for our Planck-like experiment. We briefly discuss how some of our results change for experiments with higher angular resolution and lower noise levels, such as the current generation of surveys obtained with ground-based, large-aperture telescopes.

Improving Cosmological Constraints from Galaxy Cluster Number Counts with CMB-cluster-lensing Data: Results from the SPT-SZ Survey and Forecasts for the Future

“…We follow this by presenting forecasts for the cosmological constraints from future CMB-cluster lensing measurements with SPT-3G (Benson et al 2014) and CMB-S4 (CMB-S4 Collaboration 2019). We do not explore CMB-cluster lensing systematics in this work, as these have already been extensively discussed (Raghunathan et al 2017;Baxter et al 2018;Zubeldia & Challinor 2020). We find that CMB-cluster lensing mass measurements substantially improve the predicted constraints on the dark energy equation of state parameter w from future cluster catalogs.…”

Cluster profiles from beyond-the-QE CMB lensing mass maps

“…One possibility is to stack the reconstructed lensing map and measure the average cluster mass [37,[45][46][47]. Similarly, one can obtain the mean cluster mass with matched-filtering [48][49][50][51].…”

Understanding matched filters for precision cosmology

“…Essential for the success of such analyses is the accurate determination of the mass-observable(s) scaling relation(s), which allows to link the predicted cluster abundance across mass and red-★ E-mail: inigo.zubeldia@manchester.ac.uk shift, as given by the halo mass function, to the observed abundance. At present, this constitutes the main source of systematic uncertainty in cluster number counts analyses, and, as such, a lot of effort is being devoted to the calibration of mass-observable relations (e.g., Nicola et al 2020;Zubeldia & Challinor 2020;Andrade-Santos et al 2021; see Pratt et al 2019 for a review). Any significant biases in any of the mass-observable relation could lead to biased cosmological constraints.…”