Impact of Instrumental Systematic Contamination on the Lensing Mass Reconstruction using the CMB Polarization

TL;DR

This study evaluates how instrumental systematics affect the accuracy of CMB lensing mass reconstruction, highlighting the most critical systematic effects and comparing their impact to primordial B-mode measurements.

Contribution

It provides a detailed analysis of seven instrumental systematic effects on CMB lensing reconstruction and establishes their relative severity and required calibration precision.

Findings

Rotation and monopole leakage are the most demanding systematics.

Lensing reconstruction requirements are less stringent than primordial B-mode detection for some systematics.

Instrumental systematics can significantly contaminate lensing signals, affecting future CMB experiments.

Abstract

In this paper, we study the effects of instrumental systematics on the reconstruction of the deflection angle power spectrum from weak lensing of Cosmic Microwave Background (CMB) temperature and polarization observations. We consider seven types of effects which are related to known instrumental systematics: calibration, rotation, pointing, spin-flip, monopole leakage, dipole leakage and quadrupole leakage. These effects can be characterized by 11 distortion fields. Each of these systematic effects can mimic the effective projected matter power spectrum and hence contaminate the lensing reconstruction. To demonstrate the effect of these instrumental systematics, we consider two types of experiments, one with a detector noise level for polarization of 9.6 uK-arcmin and FWHM of 8.0', typical of upcoming ground and balloon-based CMB experiments, and a CMBPol-like instrument with a detector noise level for polarization of 2.0 uK-arcmin and FWHM of 4.0', typical of future space-based CMB experiments. For each systematics, we consider various choices of coherence scale. Among all the 11 systematic parameters, rotation and monopole leakage place the most stringent requirements, while quadrupole leakage, pointing error, and calibration are among the least demanding. The requirements from lensing extraction are about 1-2 orders of magnitude less stringent than the requirements to measure the primordial B-modes with inflationary energy scale of 1.0*10^{16} GeV. On the other hand the requirements for lensing reconstruction are comparable or even more stringent for some systematic parameters than the requirements to detect primordial B-modes with inflationary scale E_i = 3.0*10^{16} GeV.