Bias hardened estimators of patchy screening profiles

Fuente: arXiv
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Main Authors: Sailer, Noah, Hadzhiyska, Boryana, Ferraro, Simone
Format: Preprint
Published: 2025
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author Sailer, Noah
Hadzhiyska, Boryana
Ferraro, Simone
author_facet Sailer, Noah
Hadzhiyska, Boryana
Ferraro, Simone
contents Detecting anisotropic screening of the cosmic microwave background (CMB) holds the promise of revealing the distribution of gas in the Universe, characterizing the complex processes of galaxy formation and feedback, and studying the epoch of reionization. Estimators for inhomogeneous screening, including some recently proposed small-scale (stacked) estimators, are quadratic or higher order in the CMB temperature or polarization fields and are therefore subject to contamination from CMB lensing. We review the origin of this lensing bias and show that, when stacking on unWISE galaxies, the expected lensing bias dominates the signal if left unmitigated. Hardening techniques that null the lensing bias have been proposed for standard quadratic estimators, whereas only approximate methods have been proposed for stacked estimators. We review these techniques and apply the former to stacked estimators, presenting several strategies (including the optimal strategy) to null lensing contamination when stacking on any large-scale structure (LSS) tracer.
format Preprint
id arxiv_https___arxiv_org_abs_2506_17217
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bias hardened estimators of patchy screening profiles
Sailer, Noah
Hadzhiyska, Boryana
Ferraro, Simone
Cosmology and Nongalactic Astrophysics
Detecting anisotropic screening of the cosmic microwave background (CMB) holds the promise of revealing the distribution of gas in the Universe, characterizing the complex processes of galaxy formation and feedback, and studying the epoch of reionization. Estimators for inhomogeneous screening, including some recently proposed small-scale (stacked) estimators, are quadratic or higher order in the CMB temperature or polarization fields and are therefore subject to contamination from CMB lensing. We review the origin of this lensing bias and show that, when stacking on unWISE galaxies, the expected lensing bias dominates the signal if left unmitigated. Hardening techniques that null the lensing bias have been proposed for standard quadratic estimators, whereas only approximate methods have been proposed for stacked estimators. We review these techniques and apply the former to stacked estimators, presenting several strategies (including the optimal strategy) to null lensing contamination when stacking on any large-scale structure (LSS) tracer.
title Bias hardened estimators of patchy screening profiles
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2506.17217