Impact of thermal SZ effect on cross-correlations between Planck CMB lensing and SDSS galaxy density fields

Abstract

Residual foreground contamination by thermal Sunyaev-Zeldovich (tSZ) effect from galaxy clusters in cosmic microwave background (CMB) maps propagates into the reconstructed CMB lensing field, and thus biases the intrinsic cross-correlation between CMB lensing and large-scale structure (LSS). Through stacking analysis, we show that residual tSZ contamination causes an increment of lensing convergence in the central part of the clusters and a decrement of lensing convergence in the cluster outskirts. We quantify the impact of residual tSZ contamination on cross-correlations between the Planck 2018 CMB lensing convergence maps and the SDSS-IV galaxy density data through cross-power spectrum computation. In contrast with the Planck 2018 tSZ-deprojected SMICA lensing map, our analysis using the tSZ-contaminated SMICA lensing map measures a $\sim 2.5\%$ negative bias at multipoles $\ell \lesssim 500$ and transits to a $\sim 9\%$ positive bias at $\ell \gtrsim 1500$, which validates earlier theoretical predictions of the overall shape of such tSZ-induced spurious cross-correlation. The tSZ-induced lensing convergence field in Planck CMB data is detected with more than $1\sigma$ significance at $\ell \lesssim 500$ and more than $14\sigma$ significance at $\ell \gtrsim 1500$, yielding an overall $14.8\sigma$ detection. We also show that masking galaxy clusters in CMB data is not sufficient to eliminate the spurious lensing signal, still detecting a non-negligible bias with $5.5\sigma$ significance on cross-correlations with galaxy density fields. Our results emphasize how essential it is to deproject the tSZ effect from CMB maps at the component separation stage and adopt tSZ-free CMB lensing maps for cross-correlations with LSS data.

arXiv comment12 pages, 4 figures, accepted by MNRAS

References in corpus (29)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• Weak Gravitational Lensing of the CMB
• Planck 2018 results. VIII. Gravitational lensing
• Mass Reconstruction with CMB Polarization
• CMB power spectrum parameter degeneracies in the era of precision cosmology
• The linear power spectrum of observed source number counts
• The Thirteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey MApping Nearby Galaxies at Apache Point Observatory
• CMB Lensing Reconstruction on the Full Sky
• Planck 2018 results. IV. Diffuse component separation
• Dark Energy Survey Year 1 Results: Constraints on Extended Cosmological Models from Galaxy Clustering and Weak Lensing
• Fast estimation of polarization power spectra using correlation functions
• CMB and SZ effect separation with Constrained Internal Linear Combinations
• CMB Lensing Power Spectrum Biases from Galaxies and Clusters using High-angular Resolution Temperature Maps
• CMB lensing tomography with the DES Science Verification galaxies
• The Atacama Cosmology Telescope: A CMB lensing mass map over 2100 square degrees of sky and its cross-correlation with BOSS-CMASS galaxies
• Scale-dependent galaxy bias, CMB lensing-galaxy cross-correlation, and neutrino masses
• Maximum a posteriori CMB lensing reconstruction
• Mitigating Foreground Biases in CMB Lensing Reconstruction Using Cleaned Gradients
• Foreground-immune CMB lensing with shear-only reconstruction
• Error analysis of quadratic power spectrum estimates for CMB polarization: sampling covariance
• Constraining Gravity at the Largest Scales through CMB Lensing and Galaxy Velocities
• Cross-correlating Planck CMB lensing with SDSS: Lensing-lensing and galaxy-lensing cross-correlations
• Cosmological constraints from galaxy-lensing cross correlations using BOSS galaxies with SDSS and CMB lensing
• Dark Energy Survey Year 1 Results: tomographic cross-correlations between DES galaxies and CMB lensing from SPT+Planck
• Dark Energy Survey Year 1 Results: Methodology and Projections for Joint Analysis of Galaxy Clustering, Galaxy Lensing, and CMB Lensing Two-point Functions
• The Atacama Cosmology Telescope: measuring radio galaxy bias through cross-correlation with lensing
• Cherenkov radiation and emission of surface polaritons from charges moving paraxially outside a dielectric cylindrical waveguide
• Impact of SZ cluster residuals in CMB maps and CMB-LSS cross-correlations

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