Impact of instrumental systematic contamination on the lensing mass reconstruction using the CMB polarization

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 7 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 result in the distortion in the CMB field and 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 on CMB lensing measurements, we consider two types of experiments: one with a detector noise level for polarization of $9.6\text{ }\text{ }\ensuremath{\mu}\mathrm{K}$ arcmin and FWHM of ${8.0}^{\ensuremath{'}}$, typical of upcoming ground and balloon-based CMB experiments; and a CMBPol-like instrument with a detector noise level for polarization of $2.0\text{ }\text{ }\ensuremath{\mu}\mathrm{K}$ arcmin and FWHM of ${4.0}^{\ensuremath{'}}$, typical of future space-based CMB experiments. For each systematics field, we consider various choices of coherence scale ${\ensuremath{\alpha}}_{s}$, starting from ${\ensuremath{\alpha}}_{s}={10}^{\ensuremath{'}}$ to the maximum of ${\ensuremath{\alpha}}_{s}={120}^{\ensuremath{'}}$. Among all the 11 systematic parameters, rotation $\ensuremath{\omega}$, and monopole leakage ${\ensuremath{\gamma}}_{a}$ ${\ensuremath{\gamma}}_{b}$ place the most stringent requirements, while quadrupole leakage $q$, pointing error ${p}_{a}$ and ${p}_{b}$, and calibration $a$ 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 an inflationary energy scale of $1.0\ifmmode\times\else\texttimes\fi{}{10}^{16}\text{ }\text{ }\mathrm{GeV}$. 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 an inflationary scale of ${E}_{i}=3.0\ifmmode\times\else\texttimes\fi{}{10}^{16}\text{ }\text{ }\mathrm{GeV}$.