Cluster mislocation in kinematic Sunyaev-Zel'dovich (kSZ) effect extraction

TL;DR

This paper examines how cluster mislocation uncertainties affect the kSZ effect measurement, emphasizing the importance of accounting for these errors in future high-precision cosmological surveys.

Contribution

It provides a detailed analysis of miscentering impacts on kSZ signals using multiple datasets and methods, highlighting the need to incorporate these uncertainties in future analyses.

Findings

Miscentering uncertainties average 0.4-0.7σ for Planck kSZ measurements.

Jackknife covariance estimates are more conservative than CMB rotation methods.

Miscentering errors at small scales can be comparable to statistical errors.

Abstract

We investigate the impact of a variety of analysis assumptions that influence cluster identification and location on the kSZ pairwise momentum signal and covariance estimation. Photometric and spectroscopic galaxy tracers from SDSS, WISE, and DECaLs, spanning redshifts $0.05<z<0.7$, are considered in combination with CMB data from Planck and WMAP. With two complementary techniques, analytic offset modeling and direct comparisons of redMaPPer brightest and central catalog samples, we find that miscentering uncertainties average to $0.4-0.7\sigma$ for the Planck kSZ statistical error budget obtained with a jackknife estimator. We also find that jackknife covariance estimates are significantly more conservative than those obtained by CMB rotation methods. Using redMaPPer data, we concurrently compare the impact of photometric redshift errors and miscentering. At separations $<\sim 50$ Mpc, where the kSZ signal is largest, miscentering uncertainties can be comparable to JK errors, while photometric redshifts are lower but still significant. For the next generation of CMB and LSS surveys the statistical and photometric errors will shrink markedly. Our results demonstrate that uncertainties introduced through using galaxy proxies for cluster locations will need to be fully incorporated, and actively mitigated, for the kSZ to reach its full potential as a cosmological constraining tool for dark energy and neutrino physics.