Title: Foreground-immune CMB lensing reconstruction with polarization

Abstract

Extragalactic foregrounds are known to generate significant biases in temperature based CMB lensing reconstruction. Several techniques, which include "source hardening'" and "shear-only estimators'' have been proposed to mitigate contamination and have been shown to be very effective at reducing foreground-induced biases. Here we extend both techniques to polarization, which will be an essential component of CMB lensing reconstruction for future experiments and investigate the "large lens'' limit analytically to gain insight on the origin and scaling of foreground biases, as well as the sensitivity to their profiles. Furthermore, using simulations of polarized point sources, we estimate the expected bias to both Simons Observatory and CMB-S4 like (polarization-based) lensing reconstruction, finding that biases to the former are minuscule while those to the latter are potentially non-negligible at small scales ($$L$$ ~ $1000-2000$). In particular, we show that for a CMB-S4 like experiment, an optimal linear combination of point-source hardened estimators can reduce the (point-source induced) bias to the CMB lensing power spectrum by up to two orders of magnitude, at a ~ 4% noise cost relative to the global minimum variance estimator.

Authors:

Sailer, Noah  ^[1];

• Search DOE PAGES for author "Sailer, Noah"
• Search DOE PAGES for ORCID "0000-0002-5333-8983"

Ferraro, Simone ^[1]; Schaan, Emmanuel  ^[2]

• Search DOE PAGES for author "Schaan, Emmanuel"
• Search DOE PAGES for ORCID "0000-0002-4619-8927"

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+ Show Author Affiliations

1. University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
2. SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Stanford University, CA (United States)

Publication Date:

Tue Jan 03 00:00:00 EST 2023

Research Org.:

SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), High Energy Physics (HEP)

OSTI Identifier:

2006307

Alternate Identifier(s):

OSTI ID: 2242446

Grant/Contract Number:  

AC02-76SF00515; AC02-05CH11231

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review. D.

Additional Journal Information:

Journal Volume: 107; Journal Issue: 2; Journal ID: ISSN 2470-0010

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

79 ASTRONOMY AND ASTROPHYSICS; Cosmic microwave background; Astrophysical & cosmological simulations; Gravitation, Cosmology & Astrophysics